We had a similar theory. We think Betsy had a medical event in the bathroom (or that led to her being in the bathroom) while Gene was sleeping. Loyal pup followed her in; during her event she involuntarily shut the dog in the closet (maybe fell against the door when the dog was inside). Gene awakens hours later in the morning, goes to check on her, opens each door to look for her outside. Dogs get outside at this point. As he's walking back into the house to continue searching for her, he has a cardiac event and collapses. (This ending is what I'm hoping; my bf discovered his father dead last year and it nearly broke him, so I'm hoping Gene didn't discover Betsy dead.)I think Betsy had a medical event which caused her death, Mr Hackman hears something, looks for her, finds her in bathroom with dog, put the dog in the closet/crate as it could have been trying to help wake her but was possibly in the way, he then went for help and either had a fall or he himself had a medical event due to the stress.
Moo
Ebm