I'm sad to hear this. It's unortunate that a heretofore responsible and trustworthy individual has lost your trust...and I suspect, spent your money!
One last conversation to have with him. Advise him he has taken funds on false pretenses. Tell him you've spoken with the police and you will file a complaint for theft if he does not immediately return your money. Explain that it is his choice, but you will not wait any longer and you're prepared to leave your home now, going directly to the police. Tell him how sad you are over this, but he has left you with no alternative.
If he now changes his story and wants to pay you off in installments, make sure he signs a promissory note, acknowledging that he took the money from you, then spent it and is is liable for the debt. Then on the back of the note, each time he pays you, indicate the date and amount.
But if you do take 'payments' make sure he pays it all up within 30 days, or interest at 20% will apply, compounded monthly, until the debt is resolved... nasty thing to do...but you're the victim.
Good luck
Fr Bill