I hope this misunderstanding gets resolved quickly, because as funny as it is for him to have to pretend to be gay for his friend, I think a clear communication between him and the girls would be in order.
Alternatively, his friend paying back the debt and talking to them for him would be even better in my opinion, because he has much more ethos with them and it doesn't seem to them like him trying to cover it up or lying to save his ass.