My mom and my brother

I've always heard that mother's treat their sons better than daughters and I've always felt that way about my mom. I live at home and I'm 19. My brother is 23 and my mom treats him like her little Prince and me like left overs. Her reasoning is my brothers trauma and PTSD. But she never got him help for the things that happened to him as a child. She instead just babies him. Never had him do a chore and pushed everything onto me. It didn't do any good. He ended up dropping out at 16 because of his social anxiety and never went back to school. He lives at home with no job and just plays video games all day. Me on the other hand, I'm expected to clean the house while my mom and brother do nothing. My mom will SOMETIMES pick up after herself but I'm expected to pick up after my brother and make dinner and have to make my brother a plate before myself. I'm also expected to do my brothers laundry which is AWFUL because he does NOT shower regularly and he pisses his bed all the time. He is more than capable but she expects me to do it. I feel like this post is coming off like I hate my brother but I don't. I hate how my mom uses his trauma as an excuse for him to never have to do ANYTHING yet also never got him help for his trauma which has pushed him so behind on being a functioning adult and now I'm expected to clean up after grown people.

Edit: I've expressed my concerns for years and of I had the money to move out I would.