Hi Karen,
How heartbreaking for all of you. I can't imagine spending all those years together and then not. My father-in-law is going through something similar, though his wife is now in a home for her alzheimer's issues. He will go out with some of the men he worked with for over 40yrs, but that is only once a month for lunch and much prodding from one of his friends. It's as if he can't give himself permission to have some fun. I wonder is your dad's golf buddies would consider getting together once and a while for lunch through the winter months? An old family friend, who I have always affectionately been invited to call Pop-pop lost his bride after 60 years. He changed so much after she passed. He wouldn't do anything, sat in his living room and just waited till he could be with her again. So sad.
I hope your dad can make some peace with his loss, and come back to being a part of his family. Anniveraries and holidays are all so difficult.
Donna