My Father has completely changed in personality and is creating issues. Any advice?

My Father and Mother live together.  I am long plane ride away.  My father thinks my mother is sleeping around (they are both 80 and 77). Of course it is not happening but my mother cannot mentally deal with the 24/7 stress of dealing with his issue. He is obsessed with it all day long and must leave but doctors think he is of sound mind. He is mentally abusive but we cannot get him to leave to a nursing home or assisted living care because he thinks he does not need it. He's essentially blind and barely can get up to go to the bathroom or bath himself. He needs someone with him 24/7. Has fallen out of his walker many, many times. What do we do. Since he has been deemed "sain" we cannot force him to go anywhere. He even wants a divorce but we can't get him anywhere....he thinks he can live in an apartment by himself. We know he cannot and it's a risk to himself that he does not understand. Completely lost with what to do....