You observed, "My experience is that teens hang out in packs & peer group is everything to them." In fact, I've been fascinated to notice over my many years of home educating that this isn't really true for kids who don't go to school.
School provides a fixed peer group of kids who are just about exactly the same age. Because schoolchildren spend 30 hours a week in this single environment, it becomes everything to them. Fear of ostracism runs deep, and jockeying for social standing can seem nonstop. Social interactions take place in the spotlight, and heaven help you if you are seen to be talking to the wrong person or saying the wrong thing. This can make it harder to develop deep friendships in which they are true to themselves.
Sure, the teens at local home ed groups sometimes hang out in packs, but it's just as common for them to go off in twos or threes. They are also less likely to stick with kids of the same age and gender, and they aren't too bothered if somebody doesn't conform to social norms. Being unpopular in one setting wouldn't be fatal to their social life, because they go to many different settings with different mixes of people. So they don't have the same craving to fit in or to be queen bees at the expense of others... and for that reason, they are used to being treated well by their peers, which makes them relaxed and friendly.
I think that this stereotypical teen behaviour which you've seen isn't really "natural" to teens. It's a response to being denied opportunities to socialise with people of different ages in different situations. Teens do enjoy the company of other teens, but also they are forced into a subculture of their own by our insistence on segregating them with their age peers, away from adults and away from younger children. It's a school thing.
You may or may not be guessing correctly that this particular boy wants to hang out with the others from his sports group. If he does want that, he's likely to figure it out sooner or later. His parents are probably aware of the situation and may be making suggestions to him. It's kind of you to want to help, but I wouldn't worry too much about it if I were you.