Who, when committing suicide, binds their arms up in their jacket? Given this and the many years of a loving relationship between the Shermans, I think it's bizarre to think this was a murder-suicide.
The murder-suicide theory has been incomprehensible to me. Everyone has a right to their opinion, of course, but I dont see how its even worth entertaining.
Just a small experiment you might want to try. Put on a coat or jacket that zips up. Fasten it. Now (if you can - takes a bit of wriggling) push the sleeves down with your hands behind you. Even without then binding your wrists, you're pretty much immobilized. (I did it; don't recommend it unless you have someone close by to help you out of it.)