Is being cordial to someone you dislike considered being fake or still having fake intentions?

I had this discussion with my husband. So here's the run down:

He doesnt like my family, but would come around my mom's house eating with family for holdiays and interacting. He isn't being rude or anything, but I and other family members see it as fake because you don't genuinely like them or being with them. Obviously being rude would only create issues which is why he is being cordial, I get that. It's just not a genuine interaction or even genuine internal feeling if you're acting like you like them/interested in them when you really don't.

For example, I don't like his older brother but I'm cordial and will keep conversation, ask about how he is doing even thought I don't like him, but because I'm doing it more so to keep peace and not genuinely interested, I see my own interaction as fake or with fake intentions.

What are your thoughts? Do you agree or disagree? Why, why not?