Mental models are just one element of intelligence, but the latest issue is internal symbolic representation. What is a "friend" beyond the textbook definition and a selected label on a person? The general direction of a solution is through a body-mind connection with similar sense feedback that is given experience similar to how a person is raised. It's through experience, sense, socialization, and language/modeling that we act as intelligent actors in the world.
The label 'friend' is mostly a shorthand used for instance when we describe our relationship with a person to someone else.
In a operational scenario, I don't think such labels are that important. We usually care more about 'how likely is this person to help me with X' (or hinder). I think this will be the case with AI too.
The question needs to be answered based on lots of detailed probability estimates (based on prior experiences and overall models), not by looking for a high level label.
