My guess, you are a friend promoting his channel which I don't personally have an issue with but if you want this to look like a legitmate effort to provide help even if it is a shamelss promotion, I would answer posts where his vidoes can answer a specific question, this would be much more effective to get their name out there.
So for example. ExclusiveAce has a series on how to get better accuracy. If this guy, stranger or friend has a video like that, look for posts that ask these questions and and post the link to that video in a comment but don't make it all addy like meaning don't say leave a subscrbe, be sure that is in the video, not in the comment you leave. Your post or comment should come across like you are providing a resource without any agenda if you want to eliminate a lot of the skpetiscm.
This is just my thoughts on your best methods for whatever it is worth. I will take a look at the videos, always looing for tips but just keep that in mind so no one in the forums gets upset for your randomly posting vids.
Chill, Have you not been on this forum before? Everyone will jump on the post and tell them this is spamming. Just giving the OP some advice on how not to appear as a spammer, 90K or not, it will look that way. That in of itself would tell people it is spam according to the rules. I could care less, love seeing YT content but there are lot of people on here that will reject it. Save your Chill's for them, just giviing the poster some advice.
Totally agree he is very underrated. I like to watch his videos where he evaluate other gamers play