Your mother has extremely unrealistic expectations of you. It sounds like she is gaslighting you too.
Maybe it’d be better for you to just lie to her & tell her what she wants to hear to avoid all of this drama.
THEN do what you can to help your brothers w/o sacrificing your own health & life after that.
I understand how you feel as my crazy parents always treated me like a free therapist. They are now no longer talking to me after I put my foot down. I owe them nothing. They abused & ignored me most of my life & yet they expect me to always be there for them! Unbelievable!
So selfish! Your mother seems to favor & care more about your brothers than you which isn’t fair at all.
Your mother is obviously mentally ill. Just tell her what she wants to hear.
Trying to reason with extremely mentally ill people is like trying to blow down a brick wall using your breath only, impossible.
They don’t listen to reason. They’re not rational or logical at all. Your mother is probably trying to manipulate & guilt trip you too. Don’t trust her again.
Please take my advice, You are obviously going to do what you think is best for your brothers. You can’t put your life on hold for them, but stop telling her that.