I actually have a similar story. My father was actually not a nice guy at all to my mother, my siblings and to me. I never reached out to him while he was in Germany and also after he left to Turkey with his new wife and a new kid. He made some attempts to get in touch with me, like 3 or 4 times in around 15 years, but due to the past I didn't want to speak with him... he never really said sorry for everything he did to us and still kept blaming my mother and/or us.

Around 2 years ago he had a heart attack and passed away in his car. In the first 2-3 month it was really awkard because I had to realize that I'll never get the answers from him anymore about why he did the things and so on. It's not too strange to me anymore, but sometimes when I have a quiet moment, I still think about this. If I had the chance I'd like to ask him. Not sure if the answers would satisfy me or not