DS is an only child. He has always had friends at school, but it has been like pulling teeth to get him together with his friends outside of school. If it weren't for the outside activities we've involved him in, I don't know that he would have much social interaction outside school. A lot of kids seem to establish friendships through sports, and that didn't work for DS. He just isn't a sports-minded kid, so we had to look for other activities that were more up his alley. This is some of what we did during his elementary school years:
- When DS was 7, we joined a church and got him involved in the youth group. They meet every other Sunday.
- DS did an art class for elementary kids for several years each Saturday morning.
- He took a jiu-jitsu class one evening per week for several years.
- He had a birthday party each year and invited school friends. These party invitations were seldom reciprocated. Our understanding is that the other families don't have birthday parties.
- Each summer, DS attended several different day camps.
DS is 14 now and has continued to be pretty busy with activities. He currently is in four bands, takes piano lessons, is in science club at school, and is still in the church youth group. Last year, he was part of an aeronautics program. When DS entered middle school, it became more important to him to see his friends outside school. He and two other boys began spending quite a lot of time riding bikes and hanging out around the neighborhood. They also spend time playing video games together at each other's houses. They have more mobility on their bikes as well as more independence, so they're not necessarily reliant on parents to organize their time together. One thing I have observed is that DS has his friends in the neighborhood and his friends at school. These groups may not intersect. DS wanted to have a few guys over the weekend after his birthday last month, and the only guys who came were the ones from the neighborhood. I found that interesting. Maybe the neighborhood friends were more comfortable accepting the invitation because they've been here before -- and their parents already know us.
DS's post-birthday get-together was a pretty casual thing. He didn't want the traditional birthday party with cake, etc. He just wanted to have a few guys over to play video games. I did have to do a little coordinating with the parents since it was an evening activity and the boys don't drive yet. We provided the transportation, offered a ton of snacks, and the boys had a good time. They all agreed they'd like to do something like that more often, so we'll find a way to support that.
ETA: OP, I have never been active on the PTA. It's not my thing either. I am actively involved in a booster club for one of DS's activities, and we are active in our church. (At DS's school the PTA really only supports the sports teams and doesn't help with any other activities.)