These kind of media reviews are tricky to do and usually I would ask you to tell us some specific claims you would like an expert opinion on. However, we do frown on baseless speculation and "what ifs" of alternate history in general. So does academic history, thus it's pretty safe to say that he's not working from many academic level sources (having watched one of his videos right now, I wonder if he's working with anything besides Wikipedia - purely because it's all very much surface level stuff when it comes to recounting actual history). I think the best thing to do would be to ask the author of the videos directly in the comments or seek out the info on sourcing on the subreddit for this channel. The wide thematic range, the fact that it's alternate history and the fact that all of it is very much simplified, seem to point to just a general fan of history with not much to back any of his claims/conclusions.