Now I think that the only thing that can be done is to fix one's owns pathologies. This should eventually lead to being properly aligned with one's self. Thereby being able to offer one's own vulnerable sides and giving loving attention to the difficult person without any ulterior motives.
This creates a situation in which the person feels actually seen and can finally "quit the bullshit".
Call it "metta", "not being in the box" or "unconditional positive regard".