I assume this is your friend and you want to deal with him as such. And that you don’t want the money to cause animosity between you.
If I’m right then your main consideration is how to do that. You can probably get the money now by forcibly insisting on your rights, and you would be “in the right” to do so.
I would suggest deciding if you are willing to risk possibly losing the money for the sake of friendship and helping a fellow Yid. If so then forget about the money for now. Consider it gone. Talk to him. Tell him you really need the money but you see he needs it even more. So keep the money for now but please return it as soon as you can.