I am so sorry for the loss of your dad.
I am also sorry for the insensitivities of the Jehovah's Witnesses around you. They are programmed to not reject the Organization or Jehovah, and to preach. That's what they are programmed to do. Like a "dog catcher" or a "tax collector", it is what they do. They are not programmed to be civil people, to be sensitive to other's feelings and concerns. And, they are not programmed on how to handle any discourse. When you have family who are "still in"; you can never be at peace. They will take any opportunity as an open door to convert you. Now, you have to grieve the loss of a parent, as well as this family rift.
Distance yourself from these toxic family members who are trapped in a cult.
Join a local group for bereavement.
Thanks for sharing.
Skeeter