fukk man. Rest up to your Mrs and condolences.
Going through it myself, I always found it easier to deal with being the one with the disease. I either make it, or if I don't, I ain't here to deal with it. 
I think if my SO went through it I would have went off the fukking rails bro..
Just remember, there's a trillion in once chance of us even being on this earth at this time. Try and enjoy what time you have left here and just know it's a blessing to even experience the simple things in comfort day to day. 
Alot of the human population aren't afforded this.