That's a rough situation jp1692. I was born in and did not leave until I was in my early thirties. I cannot recall a situation like yours. My father was disfellowshipped days after I graduated from high school. I was living at home the entire time he was disfellowshipped, so there was no shunning by my siblings and I.
I think we are all well aware of how reason, logic, and facts are pointless tools when dealing with Jehovah's Witnesses. Belief if a powerful thing. Belief is an opinion held in spite of what the facts show.
What I do know is that the following things are not found in the Bible -
"Jehovah's Witnesses"
"Governing Body"
"Disfellowshipping"
I also know the following is found in the Bible -
Honor your father and your mother is the first commandment.
Growing up there was a husband and wife who had a son my younger brother's age. I remember when I was in high school the wife and son left the husband in the middle of the night. They legally changed their names and switched congregations. I believe it was because of verbal and emotional abuse by the husband.
The son grew up, graduated high school, became a pioneer and Ministerial Servant. Then his father, who moved out of state, came back to visit. The father wanted to visit with his son, but the son refused. The father approached the local elders. Those elders told the son, now and adult, if he didn't speak with his father he would be removed as a pioneer and Servant.
So, if your father abused you, but is in good standing with the organization, you have to speak to him. If your father is disfellowshipped and you live outside the home you are not to speak with him. Such a loving arrangement.