I am so sorry for your loss. I think you did a beautiful thing by flying out to be with your father before he died. I was able to be with both of my non-Jewish grandmothers before they passed away, and that was more meaningful to me than being at the funeral anyhow. My family understood (or at least didn’t say anything to my face).
I wasn’t yet halachically Jewish when my mother passed away. I was very close to her and she was the most supportive of anyone in the family of my desire to become Jewish. She died suddenly and it was a long time before I could live with the pain of having lost her.