My son just turned 15 and I am so surprised at how many of his friends don't do anything but stay in and be on the computer or play video games.
I work so the summer is hard sometimes, but my son has a bike and skateboard, plus he babysits and keeps other kids busy. He has lots of friends who are always doing things but some....they are hermits, and their parents just kind of let them be that way.
Everybody does things differently, but having things for kids to do is good for them, in my opinion.
It's easy for kids to get the summer blahs. Stay up late, sleep late, stay inside.
Have some chores for him to do. He won't like it, but tell him for every hour he does something, he earns half an hour of electronic time. That might be incentive for him to mow the lawn or help dad in the garage or just get out.
Do you have summer recreation programs where you are? Many places have day camps and things like that. Do you have an elderly neighbor who could use someone to visit or help with work around the house? The high school my son attends requires x amount of hours for community service or they can't graduate. My son will only be a sophomore and he's already exceeded his requirements, but he still works for more credits. Animal shelters often encourage kids to come in and help feed the animals and exercise the dogs while they await adoption, etc.
There are "adapt-a-grandparent" programs.
Perhaps you can think of some things for him to do civically that will benefit not only him, but others. He might find a niche that he can call his own and feel really great about himself at the same time.
Like I said, my son has friends who just glue to the TV over the summer and sadly, all the other kids go off doing their own things. We have one friend who really hopes my son will be a good influence on her son, but she leaves him here and we keep him busy only for him to go back home and park in front of the TV. He was upset last time because my son lent his power cord to someone else before we even knew he was coming and we had no access to video games at all and my son wouldn't go get it back so he could sit in the house the whole time.
He didn't want to go to the river or the skate park or have a picnic lunch. He griped the whole time.
Sadly, those are the kids that friends get burnt out on.
I'm not saying that's the case with your son, at all, but I have friends who worry that their kids don't have any friends or don't ever do anything. It's not always for a lack of friends trying.
When my kids were little, I had them in summer school every summer. Not because they had bad grades, but because it got them up and moving and going every day. Even when I was a stay at home mom.
My son is 15. He doesn't have to do every single thing with mom or dad. He has his own little social life even though I know where he's at and what he's doing with other parents and kids I trust.
I don't think you can wait for a kid to get motivated and summer is an easy time to just lay low and do nothing.
Nothing wrong with a little relaxation, but also nothing wrong with spending the summer doing things to make the most of your time.
Definitely talk to him and look into volunteering activities. These are all things he can put down on future job applications and put toward community service hours, etc. I think he'll feel great about himself having something to do.
Best wishes.