Soul brothers forever they are!
These two have bond that will always be strong. I truly know this for fact that even death could not stop these two souls being apart.
Much like friendship in boy meets world with Cory and his best friend. Even if they get themselves wives with children at their side would not rip them apart. You can have faith that in every timeline these two friendship is forever for that is their destiny.
So you know this goes for doctor McCoy as well. Long live these three soul brothers that is their destiny to be at each other side in every lifetime.