I have no issue with this. Maybe he was diagnosed with Alzheimer's or Parkinson's? I'll tell you what, I'll do the same before either of those get bad especially Parkinson's, I watched my grandmother suffer, it scares the shit out of me.
Much respect to bow out at 71, he had a good run. This shit is legal and humane to do to animals, why not humans? Terminal is Terminal.
To do it in a cemetery, I bet he gets buried there. I can see looking around where you will be laid to rest and following through. RIP