What was wrong with the parents that he felt he had to kill them both?
He did not say what was wrong with the parents on his Larry King Live 2003 appearance. I do know that the mother outlived the father by a few years.
I recall reading--I forget exactly where--the mother died of natural causes in 1998; hers was the type of case people would think of when talking of removing the feding tube from terminally-ill patients: although removing the feeding tube may have hastened slightly the rate at which she died from other causes, I don't think she died of dehydration.
As for the father, he suffered IMHO from a fatal case of Felositis. I think he died in 2002, and prior to his death he had objected to Michael's treatment of Terri. Just my opinion, or 'hunch' if you will, but I suspect Michael and Felos wanted to shut him up permanently.
I cannot recall what was wrong with both Schiavo parents. It could have been cancer in the mother, but I am not sure. Apparently, the mother was a decent person, but she was unable to control the "monster" sons.
I don't remember what was wrong with Michael's parents. As I recall, they were on a feeding tube, and Michael Shiavo commented how good he felt whe he had the tube pulled. Amaxing that one person has three such opportunities. I wonder how much he and his two brothers inherited.