Everyday my friend gambles with his money as same with his life and he always gambling throwing away his money for nothing but losing and the worth part of it is he owes me money 
As a friend you should scold your friend to stop wasting his money if he keeps losing in gambling and also don't lend him your own money. Do you think there's a guarantee that he will pay you back? Never ever lend to someone if he will gamble it. For me, gambling is a worth playing when you have the guts to risk your money for a big win.