My son has Asperger's and like everyone else no two Aspie's are created the same. Though they tend to all have some similar characteristics.
Emotional flatness... tics (like pacing, or picking at their fingers, or rocking).... sensory issues (like my son is bothered by loud noises or multiple noises - like the tv and his sister talking at the same time).
So find out what his particular issues are and try to be understanding.
If he has food issues, like nothing can touch on his plate, don't make him eat a casserole.
If he doesn't like loud noise, don't take him to Chuck E Cheese for an outing. Don't try to "make him get over it".... like some of my relatives have tried.
Yes, it's good to help him push his limits, but don't force him.
You might read "The Curious Incident of the Dog in the Nighttime" by Marc Haddon. It's a novel (short) about a 15 year old boy with classic autism. The story is really sweet though there's a lot of use of the "F" word by the Dad (he gets frustrated and he uses bad words) but if you can get over that, I think it's a good story and it is told by the boy which really helps those of us on the outside get a glimpse of what life might be like for our own kids with autism.
You might ask your daughter if she's heard of Cognitive Behavior Therapy, which I think can really help. My son just started.
If you have any specific questions, send me a pm.