Wow...messy, if this is your "rental bidness" and the properties aren't owned outright imo. I'd try my best to "split" without "hard feelings" and keep the legal system out of it. Assuming this is your long time friend...sit down and work out a solution/split that's "fair" and TOTALLY removes each's future debt obligations with the other partner. Messy, messy, messy situation
. Good luck!