Hi Kendra,
A couple of the primary things I would do, is to ask what the seller wants to see happen. You also will want to know what caused their financial problems and if they have now solved them or not. I would not recommend allowing anyone to stay in the house (if you can make a deal with them) if they are still having financial problems.
You need to get a payoff figure from the lender to know what the debt is on the house, and as Chris mentioned, have a title company do a title search so you know if other liens are against the house.
Those would be the first steps I would recommend.
Ben