I just wanted to say that my DS12 sounds similar. He is a shy kid and also an introvert, so that can make him slightly socially awkward (i.e., it doesn't always come easily to him). According to all his teachers he has plenty of friends at school and he participates in class. He regularly talks through e-mail with a few girls who are friends, and even has a girl at school who he likes (although I'm sure he hasn't said anything to her about it). He also has some older acquaintances who are boys he sees in the weight room at school, and one chose to even honor him at his senior ceremony as someone from school who was important to him (although I've never actually heard DS talk about him).
He doesn't have any friends, though, who he wants to have come over, and he never talks or texts the kids from school. He had one friend over a couple of times last year, and he went over to this friend's house a couple of times, but this boy isn't actually the kind of kid I'd want my DS to hang out with.
When I've seen him at school with other boys he doesn't seem quite like a part of the group usually, although he is included. He is one of the few kids who hasn't been together since kindergarten, and being shy, he hasn't fully integrated in that chummy way preteen and teen boys have.
My DS is in Boy Scouts and enjoys lots of activities, including week-long camps, with these boys. But he doesn't go to school with most of these kids and doesn't see them outside of scouts. Also, when he's with these kids they are usually doing things like fishing or archery or hiking, which are not necessarily interactive. He does interact with them, but he's usually not hanging with them casually and goofing around a lot.
He also has a neighbor who is the same age, and they will "play" occasionally, but DS finds this boy bossy (as do I!) and so he limits how much time they spend together. When they were younger they would play together all day long.
He, too, would rather spend all his time playing video games or building legos. If he wants to "play" with anyone, it's usually his brother and sister.
I remember that, as a teenager, I didn't like to mix my friends from different activities (church, school, band) and I didn't really have much desire to do things outside of school with my friends, even though I had really good friends at school. I'm more social now and really enjoy seeing my friends at different activities, but I'm loathe to entertain or even go out of my way to socialize. And yet I'm a pretty successful, happy person so I'm not sure my introversion was detrimental in the long run.
Anyway, I'm no help. But I wanted to thank you for bringing up this topic. This is actually something I think about a bit. I'm never sure whether I should just leave him be or whether I should be encouraging him to have friends over.
