If you haven't got the money to gamble, its best you don't. Taking a loan for an investment is risky enough but with gambling, it is definitely not advisable. In most cases, it surely would not turn out like you expected and you would lose out like your friend did.
It seems your friend hasn't  learned anything yet and is quite strong headed. Blaming you for not giving him the loan to play and ultimately lose. It's almost laughable.

There is no game that is worth playing by taking a loan.