So Prot the alien used Robert's body as a vessel. (if you think there really was alien). But before all that happened, was Robert Porter just friends with some form of alien and they became friends and there was almost an ET like storyline going on? The earlier story was a little hazy to me.
Prot talks about this being his last trip to earth, so yes, I view Prot and Robert as old friends. Now he comes this last time to help his friend, removing Roberts (katatonic) body from the crime scene (Robert is believed to kill his wife and child's killer) and place him in a safe haven wher he gets good care. Why else would Prot stay at the hospital - he surely could go wherever and when he wanted.
For the heart life is simple, it beats as long as it can.
The sheriff also mentions that when Robert or Prot found the rapist/murderer that he snapped his neck right it two like it was nothing. Was that Robert or maybe Prot? Maybe Prot had his own issues because he didn't make it in time. He says something else in the regression about knowing something was wrong with Robert and coming back, then freaks out in the session.