Pro tip: introduce your friends to your other friends. Build a network. Networks get stronger as the number of connections increases, i.e. as more people in that network know each other. People are more excited to hang, bc they know more people, and the hangs are more exciting. And hangs become more frequent, because more people can initiate. And it makes awkward moments less common, too.
This is much more durable, reliable, and (quite frankly) fun than the hub-and-spokes model of friendship, where you just have a bunch of 1-on-1 catchups with people who know you but not each other.
Also, it's somewhat easy to do! In this guy's story, this could be as simple as, "Hey I want to get a few of us from the gym together for dinner sometime. Would you be down?" People are usually more receptive to this than they are to a 1-on-1 invite, too.