Mildly complex question

[Jeff MacIntosh]

I am in NY, my friend in Texas owns a house outright that he is rehabbing, due to some unfortunate circumstances he has run out of cash, and wants to finish the rehab and eventually sell the house. He has some overdue taxes but is not yet in any danger with the assessor's office. He asked if I would take out a mortgage and buy his house, which would afford him the cash to pay the back taxes and finish the rehab, upon which he would then have me sell the house at fair market value, approximately triple the amount he is selling it to me for. He would be making the payments, and I would receive my loan amount back plus a little extra for helping him out. My mortgage would be paid off after the proceeds from the sale are complete.

We've known each other for 30+ years, however I want to make sure I cover all the angles up to and including taking out an insurance policy on him should something happen to him, or a surety bond to make sure work is completed. What other things can I do make sure I don't end up on the losing end?