As far as any relationship between the two is concerned, from my perspective imo, one does not always follow the other around. It has always seemed imo that it's merely nothing more than the way the two friends have always interacted with one another.
Although perhaps there may have been some times when it may have perhaps seemed somewhat otherwise, it more likely than not, was not. One of the two has always seemed quite a bit more open as far as displaying any emotions or feelings and not as reserved as the other.
Because of that, although it may have seemed to be that way at times, it more than likely really was not as it may have seemed, and has been nothing more than the ways the two friends interact with one another. They have both always seemed to have alot of care for one another and alot of consideration and respect for one another as well.