I'm not an expert, but I think it's plausible. In my opinion, I don't think there's any harm in asking the question, and I would bring it up to him, but do it in a nonchalant way when you're relaxed, maybe sitting in front of the telly having a conversation, but not in the middle of a family argument for example. I would say something like 'I've heard of this Asperger's condition, does this sound like you...?'. In my own experience, I suspect I might have Asperger's, but the penny only dropped for me at the age of 39, and I am currently awaiting assessment. When I disclosed this to my family, it seemed like everybody knew except for me, but they hadn't told me and it looked like they never would, and I was quite annoyed about that because if I'd known earlier my life might have been easier! Get him to take the Asperger's AQ test, which is available online http://aspergerstest.net/aq-test/ , it's not a diagnostic test but it is a good indication of whether someone might have Asperger's or not. Hope this helps!