Wish my mom gave more credit

My brother is on the spectrum and is two years older than I am. He still doesn't know how to drive, take care of himself or his surroundings and goes to the store and spends all of his money on useless things. My mom doesn't get onto him at all (I however growing up was and it was needed) shes even made him so nervous about the dangers of driving that he is too scared to drive and she takes him everywhere.

He's never worked a full time job, only part time (20 hours is the most hes worked a week) so that my mom gets a full disability check for him. It's literally $800 dollars a month and he could be earning more full time.

I'm supposed to take over care when she passes and I keep telling her she needs to teach him how to drive because when he comes and stays with us, I'm not going to drive him anywhere, or baby him. She basically said it's my problem. I live in the country with my husband and kids and cannot stand her sometimes on her parenting with him.

He has a high iq (135) and doctors have told her how capable he is, but she just likes to baby him.

She just turned 60 and has heart problems and I'm starting to get more worried about his life and how he will live. I'd hate to put him in a group home (plus those lists are long) when I know he is capable to do better.

Anyone else have advice on this?