I'm not going to lend a friend money
Do you have a good reason for this? Why do you not want to lend him money?
He never pays me back.
You shouldn't lend money to people that much. If he won't pay you back, you shouldn't lend it out.
It makes me sad but I really cannot trust him.
I think you are doing the right thing. If you lend money you do not have then you would only end up having to borrow from someone.