Thanks to both of you. Yes, he luckily does have a card he can show if need be but so far he hasn't needed to. I'm trying to allow him to find his own way but gently talking things through with him. DH thinks that if we go in too heavy handed it may push him further towards these boys. Hopefully it'll burn out in its own time. Meanwhile we just try to support him as best we can without seeming too interfering, which is hard!
It's good to know I'm not alone, so thanks for your advice!
Mine (18) has a phone that he uses to keep in contact with me, and he checks in for advice when he needs to. It helps that he's always talked to me about things that have confused or annoyed him, and he trusts my interpretations.
Does yours have a card to show to any adult that might get involved, along the lines of 'I am a minor with Asperger's and if you want to talk to me in an official capacity you need to phone my parents on this number.' ? Hopefully, he'll never need it.
I completely understand where you're coming from, I also have a DS age 15 with AS.
He has a few friends at school who, in the main, seem very nice and sensible. A few months ago he made a new friend whom a friend of mine had seen shoplifting. Like your son, my son doesn't have a huge friendship group so I really didn't know what to do.
In the end I said nothing. The friendship seemed to phase itself out quite painlessly.
By the way, your son sounds like a lovely young man, much like mine (apart from the helpful part- the self-centred trait of Asperger's is very much evident here, unfortunately)
My very, very sensible DS who does lots of voluntary work, is very helpful, doesn't swear, smoke et al, in fact one could say he is almost perfect - well, he sees the good in most people, which is arguably a lovely character trait - anyway, he has made friends during the past 2-3 weeks with two boys, one of which I have just found out from a good source is not good news. I realise I can't choose his friends for him and he is becoming a young man but due to his difficulties he does need our help to read certain situations/people. He is still pretty vulnerable to others who may wish to take advantage of him.
I need to broach the subject with him but need to be tactful as I don't want to push him away. He is a lovely boy but is always sooooo pleased someone befriends him that he isn't careful enough.