I'd like to second Michelle Garcia Winner's approach - I have seen it help a number of kids, and there are some enlightened school systems that do a good job delivering it - thus it could be a goal and service on an IEP.
I'd also keep an eye on the academic struggles. While they may not be primary causes of depression, I am sure they play into his distress. Don't underestimate how difficult it is for a smart student to deal with classroom struggles. It can be anxiety producing, exhausting and frustrating. So, I would make sure that he has the academic supports in place, too. Sometimes it is tough to do this - especially if he is very bright and doing enough to meet minimum standards.
In addition to Michelle Garcia's work, I enjoy Rick Lavoie's book, "Its So Much Work to be Your Friend". He discusses how different aspects of LD can affect social skills and gives some realistic recommendations to help the child improve their skills. It's not targeted to an AS audience - it is more general in nature. But, I think you'll find that it is helpful.
