AIO for expecting my unemployed brother to act like an adult because my mom won’t hold him accountable?

I (27F) have always been very close with my mom. Her and my best friend of 13+ years are tied for my favorite person in the world (though due to recent events, the bestie is probably in first place). But there is a history of parentification and I think some emotional neglect in our relationship, and I’ve only realized that in the last 2-3 years.

I have a brother (24M) who was always what I’d call “the problem child”. He was diagnosed with dyslexia and ADHD before he even got into elementary school (and later in his teens would be diagnosed with bipolar and OCD). When we were young, he wasn’t great at school and would act like a stereotypical boy with ADHD. Yelling, running, obviously hyperactive, not great at managing his emotions. It tended to get written off as just “how he was” and everyone seemed to get tired of trying to deal with him, my parents and teachers alike.
By high school, he was allowed to roam the neighborhood on school nights after midnight, smoke weed with his friends inside and outside our house, and even set an abandoned building on fire (whole thing did not burn down, but they apparently made a fire big enough to attract the cops, but my brother and his friends had run off before they did) and tried to barge into his ex-friends house with a baseball bat. My mom also regularly did his high school homework for him just so she could get him through graduation.
Meanwhile, if I got below a B in a class, I was grounded and often got very demoralizing talking-downs to. I was often made to feel like I had to be the quiet, well behaved kid to make things easier on my mom, but sometimes even this wouldn’t work. (I waited until I was 18 to ask my mom for permission to smoke weed with friends for the first time, if that tells you how much of a people pleasing weenie I am.) If my mom was in a bad mood, there would often be stomping around the house and doors slamming. Dishes tossed into the sink angrily. Sometimes some “yelling” but not necessarily screaming if that makes sense. Regardless I think it wrecked my nervous system lol.

Ultimately I had sorta gotten over this after going to college and moving about an hour away. Didn’t have to deal with him or the discrepancy in treatment much from that far away. I visited regularly, but I had my own apartment where I could be myself and I was pretty much self sufficient. It’s also worth noting I got diagnosed with ADHD (late diagnosed sisters with early diagnosed younger brothers where you at? Lmao) as well during this time, on top of my generalized anxiety and depression.

Well a couple years into that cozy living situation, I got stuck at a pretty toxic workplace for 2 years. Not much work-life balance, absolutely inefficient processes and workloads, and a boss who seemed to have it out for me. This was back in 2023, so the job market was bad (not as bad as now, but certainly bad) and after applying to I think 50+ jobs while still working the awful one I finally broke down and told my mom I had to quit or I was going to hurt myself, either intentionally or unintentionally. Could barely make myself get out of bed in the morning and when I got home every night I’d cry. Eventually my mom gave me permission to give my two weeks notice without a job lined up (and I know that sounds ridiculous from someone in their mid-20s, but on top of basing a lot of my worth on her/other’s approval, she also helps me financially with the student loans I have and would be helping me a lot financially while I was unemployed)

Ultimately it took months of no luck with getting a job in the city I lived in, so I decided to move back to my hometown where my mom was, and therefore my brother. My mom has some serious medical issues since the pandemic, and so being closer to her day to day also sounded really nice.
My mom was kind enough to offer to get me a house (as in, she would own it on paper, but I’d pay her rent to cover it. I have about 60k in student loan debt + car and credit card debt and cannot get approved for any house loans. Tried and failed a few times sadly) so I wouldn’t have to worry about being beholden to an apartment’s rules or be concerned about being evicted if I hit a rough patch financially. She’s very understanding of the fact that it’s hard for younger adults to get established these days, which I appreciate and love her for immensely.

However, she wanted to do the same with my brother to get him “set up” or whatever. At the time he was working as a full time custodian at night, had been for about a year at that point. I had gotten a full time job in town finally (public service, and had to take a pay cut due to the lower cost of living/lower wages in a smaller town). She convinced us that the best way to get us both set up would be to buy us a single house with 2 bedrooms and me and my brother would be roommates. I agreed after being assured of 2 things:

1. He would have to keep up his end of the deal and keep a steady job and pay his half of bills and rent.
2. He would not smoke weed on the main floor of the house. (This is largely due to the smell but also because I really wanted to have future coworkers over and didn’t want to risk it being seen and my job being at risk. I’ve smoked weed before and have no moral issue with it, but it is illegal here still and I’d rather it be kept quiet and as inconspicuous as possible if he’s gonna do it)

I think you can guess where I’m going with this. We got the house, but about 4 months in he began smoking weed on the main floor of the house. Okay, whatever. I’m not about to start a fight over that, especially since at the time I had been working a lot of seasonal overtime and had no energy for fighting. A month or two later, he got caught sleeping on the job. This was also after he decided he could go in when he wanted and leave when he wanted without letting his boss know. His reasoning was, and I quote, “Well if there’s nothing left to do it’s better to sleep [on the job].” He had his hours significantly reduced and was also told he’d have to clean a different building for the organization he worked for.

Well, he didn’t see the point in that and decided he didn’t want the job anymore. But instead of him being an adult, my mom texted his boss for him (on her own phone!) to quit for him. It has now been almost 2 years that he’s been unemployed.

I now pay all the bills, and for a while was still paying my entire half of the rent (his was $450 because he got the slightly smaller bedroom, mine was about $525 since I chose the larger one and also had a better job and more experience with “adulting” if you will) to my mom while she paid his rent for him. She paid me for his half of the bills for a while, but it basically ended up being what I would pay her in rent monthly and a bunch of money would end up being tossed back and forth between us for no real reason. Ultimately we decided I’d pay half my rent and all of the bills. This has been the case for about a year now. And, admittedly, she has been pretty lax about if and when I get that rent to her now as I recently got approved for a debt consolidation loan to try and pay off my credit card debt. So I’m not saying she doesn’t help me out. She does and I’m immensely thankful for it.

But, am I crazy in thinking the disparity in expectations and treatment between me and my brother is insane? He does not clean the house (or if he does, he maybe picks up a few things and throws them somewhere else, so it’s just as messy/dirty, it’s just that the floor is clear). He even got pissed a few months ago, said that I wasn’t doing enough around the house (after working 40+ hours a week!) and started throwing trash in my room, and called me a “dumb bitch” for daring to say he needed to either get a job or he needed to take care of the house since he was home. all. day. every. day. We both have cats, and yet I’m paying for all the food and litter. I had to literally make the appointment to get his cat fixed for him, and my mom paid for it! (Worth noting I would not have even done that for him if it weren’t for the cat going into heat every month or so absolutely destroying my sleep schedule. Purely selfish on my part, though I’m sure it makes no difference to him.) I could go on and on with more specifics but it feels like I’m expected to be a secondary mom and baby him like our mom does, but at the same time I’m not allowed to be angry or put down boundaries when I’m frustrated with the double standard. And I certainly wouldn’t be able to get away with being unemployed for as long as he has been, on her dime (and mine).

TL;DR - Am I overreacting when I try and “parent” my unemployed adult brother because my mom never really has?