The relative called difficult may be the first to stop translating discomfort into politeness.

Every family runs on a certain amount of translation, where irritation comes out as a compliment and disagreement comes out as a change of subject. The person labelled difficult is often just the one who stopped doing that work. They say the discomfort plainly, and the room experiences the plainness as the problem rather than the thing being described. The label protects everyone else from having to answer what was said.

When someone in your family gets that label, try separating the delivery from the content for a moment. Ask what they were actually pointing at, and whether anyone else had noticed it and simply chosen a softer route. You do not have to agree with how it was said to take seriously what it was about.