How do I deal with my family.

I 32F have been battling with this for so long I just really don't know what to do at this point. Bit of back story.  I grew up with 2 older brothers we are gonna call B1 (38) and B2(37) . We grew up on a farm and our parents were very happily married. We didnt have alot but we were happy and a pretty close nit family. That was until we weren't. When I was 11 our dad died of cancer and its tore our family apart.  As a teenager I was pretty angry and lonely but thats a whole other story. At 19 I ended up in mental health hospital for 2 months after a s****de attempt. This is when I really started to see the true nature of my family. B1 at the time didnt have a car and I decided he could borrow mine while I was in hospital. I still owed $32,000 Australian dollars. I was expecting this car to be handed back once I got out. He said all good. 2 months pass and I get out and I find out that he had sold the car and bought himself a new one and a bunch or other stuff. Still to this day I have not received a cent an apology or a car.  I eneded up going into bankruptcy after fighting with the financial company for over a year. Over the years little things have happend and I just get told "its family " so I have to sweep it under the rug. Like when he said he was happy I had a miscarriage because his wife was pregnant at the same time and it took the shine off him.( I should mention I have a 10 year old step daughter who I have raised since she was 2 and consider her mine and a loving partner.)  Anyway I could go on for hours at the little thing but flash forward to Jan 2025. We had a party to celebrate dads life being 20 years. My best mate who i have know since i was 9 dated B1 but they broke up 15 years ago. They remained friends until her met his now wife when she "forbid " him to see her. B1 asked my best mate to be secret friends but she refused. They both have children and partners and havent spoken i almost 10 years. I invited my best mate as she new my dad and shit hit the fan. Suddendly i was this horrible person and B1 started bagging me out the entire family. Extented family included. So i made arragment for her to come after he left. He never showed up, but continued to bag me out because how dare i be friends with someone whos been there for me since I was 9.  Fast forward to Christmas 2025. The one day a year we actually pretend to be a family. B1 decided for the first time ever to host the family christmas and plan a camping trip for new years. He flat out said my partner, my child and I were not welcome and we can get f***ed. i have looked after our mum for the past 15 years financially and things she needs done that she can no longer do, with no help from either brother,(this has annoyed my partner at times as she thinks mum takes advantage of me but its my mum how can i say no) So I would have expected her to atleast stand up and say somthing but she didnt. Noone did they all just excepted it and since then i have  refuse to do all the things in used to do for mum. And now im a horrible person, lowlife , narsastistic these are just some of things that have been said to me and i have been excluded from every family event since. I am a vet nurse who works my ass off to provide for my family and im so proud of who I have become amd for the people who are ment to love me the most tare me down and hurt me the most. Im just stuck I love my mum but im so torn keep hurting like this and its killing my partner to see me like this but ive had "its family" drilled into my head for 32 years. What do I do? . ( B2 is very silent and always has been when it comes to family drama and follows big brother like a lost puppy) .