Psycology doesnt help autism much. Id say an older ASDer needs an autistic specialist in social skills, a job coach and somebody to help with life skills. This is not a psychological condition. Its a neurological difference. They may also, say, have depression too, but the biggest issue is life skills. Unless taught them, they may never learn them.
And they may remain clueless and childish forever. We started early but its never too late.
Neuropsycologists are good.
Lots of luck!