I'm looking at various monster charm abilities. It seems like each gives the charm condition, plus other things.

I'm looking at the charm ability of Strahd (spoilers ahead)

"The charmed target regards Strahd as a trusted friend to be heeded and protected. The target isn't under Strahd's control, but it takes Strahd's requests and actions in the most favorable way and lets Strahd bite it."

If a PC trusts their party and considers them friends, and Strahd charms them... then what? Who do they side with? If Strahd said "get into engagement and fight the sorcerer" to the charmed monk, would they just do it?

There's his tactic section that states " At the very least, he can order a charmed character to guard him against other members of the adventuring party."

How would that play out?

I imagine it would be persuasion checks maybe, with strahd having advantage?

Edit: if the charmed PC has an object of value, and both the rest of the party and strahd wants it, would that play out as persuasion checks?