How do adults make friends
Look through their trash when they’re asleep
“Since the lockdown kicked in I’ve been stuck without any new books. Do you have any good ones you’ve read recently or a favorite I haven’t heard of?”
Bug their phone, search their home, interrogate their family and friends, hire a team to tail them and document everything they do. That’s a decent start I think and it won’t make you seem pushy like asking questions would do.
Just hang out with them.