singular vs plural - I don't like the look(s) of him

Here's a quote from an American animation "Trolls":

[referring to Cloud Guy]

Poppy: Branch, he's trying to help us.

Branch: I don't like the looks of him. I mean, who wears socks with no shoes?

Poppy: He seems to know what he's talking about.

Cloud Guy there is a character in the animation that looks like a cloud but certainly acts like a guy, i.e., anthropomorphic.

So it's as if you're talking about a guy who "wears socks with no shoes" and you don't like it. In this context, is it correct to say "I don't like the looks of him" instead of "I don't like the look of him"?

Is it also correct to say "I don't like his looks" instead of "I don't like his look" in the same context?

If the plural "looks" is correct in the given context, when should you use the singular "look" instead and say "I don't like the look of him." or "I don't like his look."?