I agree with you. That is awfully young, and as the mother you should obviously be consulted – and I would say “in agreement”. It sounds as if your stepfather is trying to buy affection from your son (certainly not from you!), so your best method of damage control now is to maintain strict control of how and when he rides, including when and why he doesn’t ride, as the carrot to make sure that homework and chores are done, etc. At this point you can’t very well take it away, I presume, without coming off as the mean mom. But you may need to consider that, too. Someone has to be the adult.