From Julian Lennon's page on Facebook

[liberalhistorian]

31. I agree with you on that, he did recognize

the dickbag he'd become and was really trying to work on changing a lot of things about himself. Some people never get to that point and never do any introspection and continue to be dickbags, so at least he was trying. Of course, being married to Yoko would be enough to make anyone crazy! He was just starting to recognize how badly he'd been treating Julian (when he wasn't ignoring him and favoring Sean, that is) and was attempting to rectify that when he was murdered. Unfortunately, the crazy bitch Yoko basically shut Julian out of everything, including any real inheritance of John's, and has always treated him like shit, that is, when she's even bothered to acknowledge his existence. She resented his very existence from the beginning and I have no doubt that she played a very large role in John's bad treatment and ignoring of his own son. As far as she is concerned, Sean is the only child of John. I will never understand stepparents who pull that shit, ever. Bitch.

And let's not forget that the way John was raised wasn't all that ideal, either. His uptight aunt basically took him from his mother, even after she was remarried and her husband was quite willing and prepared to be a good stepfather, and he didn't see her very much before she died in an accident when he was just a teenager. He never had a real "father" figure in his life.