Dustin, my mother passed away at the end of March. She had been very sick for quite some time, and I knew that eventually I would be faced with the same decision you are. I have been out of the Borg since 1991, while my mother remained "faithful". We had a strained relationship for years. However, I knew it was her wish to have a Witness funeral at the Kingdom Hall. I also knew that most of the people who would attend were people I have known since I was 12 years old. So, I struggled with what I should do and how I should react when the time came. When the time did come, I went through with her wishes and put my best face on. I figured that staying away wouldn't make a point or any kind of impact. It wouldn't change a thing. The only one who would regret my absence would be me.
Right before she died, I sat with my mother in her hospital room for three days after she slipped into a coma. Witness well-wishes came and went and were polite but not comforting or friendly. At her memorial service, I sat up in front at the Hall with my younger (unbelieving but never baptized) sister and my kids. For the hour I was at the Hall, not one Witness said a word to me. After the service, my younger sister had everyone over to her house. Everyone ignored me there also. I didn't care. I shunned them as much as they shunned me. I was there for my mother. After 48 years of being my mother, it was the very least I could do.
Sometimes you have to swallow your pride and do the right thing.