It happens a lot with those close to us and sometimes we don't realize that we could have done something more until it is too late. I have several people in my heart now where I could have but did not. One of them was my mother. She never blamed me that I can see although she had good reason to...i watched my dad turn back into a nice little kid before he died; took a few strokes, and imo it needn't have to happen that way, but i dunno, and that is what i witnessed. He became someone whose mind had changed, that i could love. I'm sorry i couldn't take advantage at the time, I'm talking about a guy wild birds basically came and perched on his shoulders
I've never had a family member close to animals or birds like that but I had a close friend who had an unusual connection with squirrels.
You will never forget your dad and what he was and what he became. That he made a difference to you is seen in the words you posted here. For as long as you can remember anything you will remember him.