Well what behaviors? I mean there are some things autistic people can improve on and certainly work on behaviors that can hurt or excessivly bother people...but most of us can't just 'act normal' for an extended period of time so if that is what you're expecting you'll be out of luck.

But if there are certain things he does that really bother you or are harmful you can ask them to not do that, talking to the superviser/employer is good but obviously they don't see a major problem. But yeah what is the problem with how he approaches you?...there might not be a lot he can do to change that depending on what exactly your issue with it is.

If he doesn't know he could be on the autism spectrum, I don't think there is anything wrong with mentioning it and suggesting they maybe look into it...maybe that would help some. But yeah people with autism have brains that work differently than normal so there are going to be some rather unusual traits people with it have its impossible to mask all that and be 'normal'. Sometimes tolerance is needed on both sides.