AITJ for telling my brother I’m not covering for him at our father’s hearing anymore?

I’m 38M. My older brother is 44. Our dad owns a small supply company that he built from scratch, and for most of my adult life the unspoken family rule has been that my brother is "great with people" and I am "great with details," which really means he makes promises and I get stuck cleaning them up.

About a year ago Dad started stepping back for health reasons. Nothing dramatic, but enough that vendors and clients began dealing with us more directly. My brother immediately slid into the front facing role. He loves being the guy shaking hands, taking lunches, calling everyone "my friend." The problem is that he also says yes to things before checking inventory, pricing, delivery windows, labor, anything. Then I get the email chain with some version of can you make this work.

I have made it work more times than I want to admit.

Three months ago he closed a contract with a municipal buyer and promised a delivery timeline that was never realistic. I told him that the same day. He said not to be negative and that he would smooth it over. He did not. We missed a benchmark, then another one, and now there is a formal dispute over penalties. Our dad has a hearing next week with the board that oversees the contract because his name is still on the company.

My brother asked me to attend and "keep the story straight."

By that he means leave out the emails where I warned him, leave out the revised schedule I sent that he ignored, and present this like a vendor delay nobody could have predicted. He actually said there is no point bringing up internal disagreement when the goal is to protect Dad.

I said I will show up if I am asked for facts, but I am not going in there to help him turn his choices into bad luck. He got furious and said I care more about being right than protecting family. My aunt called and said the hearing is not the time for principles. My mother cried and asked why I cannot just get through one afternoon without "making a stand."

That part messed with me, because I do love my dad and I hate that his name is attached to this. But I also feel like covering for my brother is part of how we ended up here in the first place. Every time he overcommits, everyone expects the adults in the room to quietly absorb it.

Now he is telling people I am choosing the perfect moment to humiliate him over old resentment, when from my side this feels like the first time I have refused to help write fiction.