Read slowly now....THEY CLAIMED THEY'VE BELIEVED MICHAEL PUT TERRI IN THIS POSITION FROM THE BEGINNING.
And you read slowly now...THEY COULD HAVE DISCOVERED THIS AT SOME POINT AFTER TERRI WAS PUT IN THE HOSPICE!
No one wants to belive that their son-in-law would do this to his wife.
But after a time when you begin to add things up and put two and two together it's logical to look back on everything and realize as you said in your own words "that the believe Michael put Terri in this condition."
"from the beginning" doesn't automatically mean that they believed from the moment Terri arrived in the ICU that he had something to do with it.