I am in a somewhat similar situation…the guy who used to fix my computer when it acted up is the one I now have to show how to do things on his phone and iPad. The decisions we used to make together, are now pretty much mine to struggle with, as he gets bogged down in details. We’ve been married 51 years, and I feel not only am I losing my husband, but my best friend. I find playing the piano does help, and he enjoys listening. Maybe picking up your music again will help you both. Best wishes as you travel this scary path.