Thank you to everyone who convinced me to go visit my grandma?

I am sorry to hear about the loss of your grandmother. I wish I knew of a way to help you help your father cope but I struggle with the same issue since my husband loss his sister 2 1/2 years ago and still struggles. I think the main thing you can do is be there to listen and allow him to go through the different stages of grief without telling him "to get over it" or "move on" (not saying that you would). Realize that he can be stuck in one stage for months or even years.