Yes, you can sue him for the money that you paid on his behalf and to satisfy his obligation.  Listen, if they had foreclosed on the time share then they would have come after not only you but him as well for the money left owing on the mortgage.  So you saved him from that whole scene.  You may also be able to sue him for the interest on the personal loan here but one would need to review the documents involved and the law (it was your choice to take out the loan and pay off the mortgage; really your could have continued to just pay it).  Seek legal help here. You need to get his name off the timeshare as well.  Good luck to you.