AITAH for telling mom to stop supporting my brother

My brother is 27 years old and still lives with my mom without a job or going to school. There is a question as to whether he is autistic or not. He struggles with eye contact and communication and while that seems like a smoking gun, I feel like it's self inflicted. He spends all day on the computer and when we manage to bring him out he doesn't talk and opts to stare at his phone.

I've never been close to him, but I do care about him missing out on life. I've been messaging him asking about his plans on life and what he expects to do when our mom can no longer take care of him. He ignores any attempt at communicating. I decided to escalate things and tell my mom I feel like there needs to be a deadline for him to step up and do something, start contributing, make moves towards self sufficiency.

I sad he sits on his ass... she flipped and started crying saying that he helps with laundry and cooking.... to me this is a weird co dependent relationship. am I the asshole? should I cut off all ties or continue to help get him out of a terrible rut.