If you mean that the mortgage company foreclosed on the house then do not pay him any more rent. You may want to be sure that is what happened before you stop paying though. If the mortgage company did foreclose then they will be contacting you about moving out. I advise my clients in those situations to be looking now for a new place to go. You don't want the mortgage company to demand that you move out quick and you don't have a place to go.
When you say he "lost the house" do you mean the bank foreclosed on him? If so then don't pay him. Wait for the bank to contact you most likely through a real estate agent. Unless someone bought the house through a foreclosure sale - then they should contact you. But if the owner/landlord still owns the house you have to pay. And if you owed him some past rent you might have to pay that too. You should sit down with an attorney for a consultation to determine your rights.
