Some friendships in life sustain themselves only at a particular life stage, products of some mutual developmental problem to be resolved together, or of some external circumstance, like being housed in the same dormitory in boarding school. Others grow out of a deeper spiritual and philosophical affinity, which continues throughout life.
There's an infantilization that happens to actresses in general - musical theatre, straight theatre, television, film - we're spoken to like children. Actors are spoken to like children a lot of the time.