I haven't been in your situation but I am a nurse and i do see this happen alot. At first, they are just seeking someone or something full of life so they don't have to deal with the death. He isn't doing it to forget your mom, I'm sure you know that will never happen, nad from what I see it begins to change back after awhile and they want to be home again. My heart goes out to you and I hope everything turns out okay. I will keep you and your dad in my prayers.