Hmm.... would it be wrong to charge Gil in order to train people how to play as opposed to just carrying them through content?
The problem is it's not as simple as teaching people how to play; otherwise, "good" players would just be one-shotting raids as they came out.

This game's difficult content is only hard because it's so heavily scripted with punishing mechanics. It's more about trial/error and memorization than it is about "learning to play" and simply being reactive.

However, if you offered a service that actually trained people to beat specific encounters, then that would actually be pretty sweet. One of the biggest barriers to learning is finding seven other people who can help you make progress to learn later stages, and a service like what you've proposed would immediately address that.