Besides all the stuff related to sex that many people have already written down here:

1. That it is normal to have overwhelming emotions at this age. It’s fine if he gets angry, or sad or whatever. Find an outlet for that emotion.

2. He is gonna get a long stronger. It is important to approach this with sensibility: saying stuff like “strong men are dangerous” or “men are strong and women are weak” etc can actively harm young men’s mental health. I’m sure there are good resources for this online as well, though I’m not sure where. He needs to realize that he will need to control how much force he puts into things much more than as a child, but at the same time that people are not afraid of him and should not be.

No? Simply wait with that part for one year. That should not be too hard

Well depends if we’re talking for instance admins, developers or users/mods. Would probably need different models.

Sub.club wasn’t successful in offering a content monetization model on the fediverse

Well yes, the whole concept of the fediverse is that of social media as a public service. All activitypub data is public.