He's not still on Luvox, right? Combining Luvox and Seroquel isn't recommended.

Also remember that a person with autism can be mega sensitive to medication. What is a normal dose for a "normal" person can be a grave overdose for an autistic individual, also "us" autistic people have more out of the norm reactions to meds. Can take a while finding something that works. What is his worst problem that needs to be addressed?