You don't really know why he isn't responding. His father just died, and he probably has A LOT of responsiblities and grief. I know when my mother died, I had no energy because of all the arrangements. When I would get home, I just needed to sit. He may not be avoiding your calls, just overwhelmed with the circumstances.
For some reason, when death is involved, a lot of JW's will soften on the shunning bit. You will only know if this is the case if you attend the funeral service. You have the option of leaving if it upsets him or you too much. Minimum, send a card and maybe flowers if they are accepting them. He needs to understand that you are not demonized and still have the grand capacity to love.
I'm sorry for your loss too. If he was your best friend, I'm sure you knew his father, even if it was only a little.
Take Care,
NC