You won't believe this but I see met with weird sexual problems for a living. A guy who gives women money on a regular basis always has strings attached (no matter what he says). That is a favorite ploy to make the woman believe that he's doing it out of the goodness of his heart. That's never the case! There may be a friendship (on their part) and he has developed and maintained this facade over a period of time. Eventually there is a cost! When it finally happens she will be very surprised and feel very silly. This is called the grooming process. At the end of the process there is always an emotional or sexual payoff. I would strongly encourage her to end this asap. He is just baiting her but of course he won't tell her that. As far as your relationship, I would encourage her to end this immediately because eventually it will be sexual. Nothing in life is free and this includes his money. He is buying her affections and will attest to how his intentions are honorable. No they are not.
Encourage your girlfriend to refrain participating in this situation. Find anoher way to make ends meet because eventually he will want her to pay up. Guys that give out money to younger women for no reason are not their friend.