My understanding is that John and Paul patched up their differences before John died. The "rift" between them was never as deep or ugly as the music press in particular liked to portray. I have several interviews on DVD and in print where both parties admit they would always be close and I don't think this is just wishful thinking on the part of the fans. The recently broadcast TV documentary covering the day John Lennon died featured an interview with Dave Sholin, head of the RKO radio team who conducted the last ever interview with John. Dave himself was one of the last people to chat informally with John, aboard the RKO limo which gave John & Yoko a lift to the Record Plant when their own car failed to show up.
Says Sholin: "So John is saying, "Well, our car isn't here. You're going to the airport, would you mind giving us a ride?" I said, "Hop on in." And on the way, I ask him about his relationship with Paul McCartney. He says, "Well, he's like a brother. I love him. Families – we certainly have our ups and downs and our quarrels. But at the end of the day, when it's all said and done, I would do anything for him, I think he would do anything for me." And we said our goodbyes and dropped John and Yoko off at the studio.''
Paul has also gone on record many times expressing his relief that they parted on good terms, i.e. their friendship restored.
I think confusion creeps in because on the last occasion Paul happened to "drop by" John was a bit vexed and reminded Paul it wasn't quite like the old days when, unannounced, they'd pop into one another's houses as kids back in Liverpool. But these are the kind of mundane throwaway things we all say in day to day life which carry no great moment and I'm certain that they knew each other well enough to realise this had no "edge" to it. I think if they'd ever for a second realised they'd never see one another again they'd have been hugging each other like brothers.
Slightly sadder to me is the more likely fact that John passed away sulking with George, whom Lennon felt had paid him scant respect in Harrison's then current autobiography "I Me Mine". I did read that George had subsequently tried to contact John, who had failed to return his call before the terrible events of December 8th 1980 overtook him. So, unlike Paul, George lost his dear friend John on a slightly sour note - though again, had anyone had an inkling of what was coming I've no doubt in the great scheme of things John and George loved each other to the end.
"Life is very short...."
You don't go through the highs and lows those four guys endured without forging a deep and lasting bond.