We all make decisions mate, rightly or wrongly and sometimes we can regret them but at the time of making them they make sense.
My dad passed away last August (he left us when I was 11) but growing up, becoming an adult and a father myself I tried time after time to get the relationship to work but it wasn't to be. I didn't attend his funeral, I never got tosay goodbye, never got to say I love him, never got to pull him up over all the pain he caused the family over the years.....but....my conscience is clear with my particular decision and every now and then a song comes on the radio that reminds me of him and I look up and say "hey you daft sod I hope your alright and I still love you".
Sorry mate, probably gone off on one a bit there haven't I. I just wouldn't want you beating yourself up when I reckon you would have made the decision in good faith at the time not to go the funeral or not try and speak to him at that particular time.