Plenty of good advice in this thread.

I’m gonna shout out the boy version of the book “what’s happening to my body?”

https://www.amazon.com/Whats-Happening-Body-Book-Boys/dp/1557047650

It was super helpful to me in puberty, even with trusted male figures. It’s written from a non-judgemental, information focused space. It also let’s him has some way of privately seeking knowledge that isn’t just whatever he finds on the internet