Any guides you recommend for streaming/community building (on Youtube)?

Hello, my friend started streaming on Youtube in a small niche 3 weeks ago for 2 viewers (me and another friend), we had fun, people joined in, things grew. Last night his 6 hour stream had on its peak 2000 concurrent viewers (with 1000 on average I guess) and Youtube showed him that it had around 50.000 views overall.

During this last 3 weeks I have given my friend some tips (I needed to tell him to ask people to subscribe, adviced to create a patreon, let him mention that people can donate, try to recognize some recurring viewers who can help with moderating his chat, etc) which helps monetizing his streams/video's and overall create a more fun community. All great, but my experience is limited to just being part of the internet and communities since a long time where he is a little more tech/stream/community-illiterate.

So, I'm not a streamer, but I would like to help him succeed. If I could show him a blog / ebook / video-series on all sides of having a stream. From basic stream tips like consistent scheduling to what kind of software to use, overlay graphics etc etc.

Anything you can recommend? The things I found on the internet where mostly just plugging certain affiliate links. I don't have an issue with that, but reading it made me almost feel that it was only written to plug those links which makes me doubt the validity. So if anybody has some good recommendations, would love to forward those!

Thanks