You might have better luck getting this punted to mental health instead of developmental disabilities.
Why...
My husband was told because he made it through high school and some college, his developmental disability was not the issue. His depression, anxiety and OCD are a huge issue.
Any help is geared to the very low end of the spectrum. Can he wash, feed, bath himself? Can he make a shopping list and go shopping? Read a bus schedule and figure out a route? Cook without burning down the house? Balance a check book and handle a bank account? Help is given for people who can't do that.
My husband's Aspergers is considered secondary to the mental health issues.
You son might help through some jobs work program. They might drop him into any job the counselor seems fit.
My state gives basically nothing to adults are not severely disabled (non verbal and need ADL care). My husband could benefit from speech therapy, PT and OT. There is not one provider who will work with him, even if we pay cash.
If he was my son, I would apply for SSI. It's a three year battle, and you have nothing to lose. With the mental health issues and ASD he might it get, and that will give him some breathing space with some money coming in.
Also remember, your son is not a red hot to the state. He lives with you, and you deal with the fall out. So they don't care if he works or what not because you are there. He isn't living out of the street, and pan handling. He's not starving, and single men get the shaft when it comes to government help.
Look into a community college. They sometimes have better programs for ASD people, than the state will prove.