An any desperate gambler should went though the path which he first loses his own and then someone else's money. Only when with no money and when no one wants to give a new borrow, comes the realization that the wrong way of earnings has been chosen. This road (good gambler) for those who are lucky. You just have to learn a lesson and tell to your friend how it is.
This really is a desperate gambler's move, the urge to gamble is so strong that he cannot resist that he has to borrow money from a friend, if it is his birthday and he wants to have a good time, we can accept this, but to the point of making a loan to gamble, this is a symptom, of gambling addict, you will only loan money when you badly need it, or you have a good project ahead and gambling is not a good project.