With information at one's fingertips, I don't want him to watch a random YouTube video and fall down the rabbit hole of "trendy" things.
For now, the only advice I gave him was to NOT use AI to write programs. Think on paper, then type on the computer. Avoid LLMs as long as possible to develop logical thinking.
He grew up watching YouTube (random TV comedy programs) during his free time. Thankfully, he has no addiction to it or to his mobile. He has rarely read any books (fiction or non-fiction), so I'm not sure how to suggest the importance of reading and writing.
I would also suggest Anki SRS.