Terri who became brain damaged ... with only Michael present.There is no proof that Michael was the only person present when Terri "collapsed."
I wonder if a girlfriend of Michael's had a key and she, or a male friend, used the key to enter the apartment that night.
Or perhaps Michael let someone into the apartment while Terri was sleeping.
Terri may have thought, during the first years of her disability, that Michael did not want her dead.
The complex they lived at was really pretty upscale on the way out of St. Pete to the causeway to Tampa. Terri's brother Bobby lived there too but in another building. There are lots of bldgs, some gazebos and a curvy parking lot. I have no idea if Mikey acted alone but it took him a long time to do anything. Then Bobby showed up to see what the heck was going on.