I started a little full-stack bootcamp to give back to the community, I had about a 50% success rate teaching people from all types of backgrounds, economic and educational levels etc.

I typically charged a couple hundred bucks so that they would have "skin in the game". 100% of the people, I or someone else funding, failed to finish the course. Having skin in the game is absolutely critical to their success.

In this case, it seems they have nothing to lose, and I suspect if they are willing to beg you for cash, they would have no problem going elsewhere.

I suggest some sort of deal where he has to put something in other than "time and effort". Perhaps have him "pay" you in other ways, such as chores around your house. Mowing the lawn, etc.