This is what I think it means.

It depends on the year, the country, and the specific milieu in which the conversation takes place. Actually, it depends on the characters and how those characters choose to express themselves.

However, I totally understand that you might be on a tight deadline, so I'll just go for it.

I'm from the UK and working from the English I know.

This is supposed to be funny and that's a matter of taste as well as of whatever fits the characters best.

-Who, ...him?
-Yeah.
-But he's a total troglodyte.
Joselo doesn't understand her/his comment, and makes this abundantly clear with his eyes.
-Beast, Joselo, he's a total beast!
Joselo lets out a laugh big enough to necessitate placing his wine glass on the table first.

Brute is correct but I think the register might be too high or might only be something someone quite posh or old-fashioned might say. Again, without the context, it's hard to say.

Ignoramus is funny, but would depend on the context of the story. Is the man's appearance what's most important?

I was trying to make it funny by choosing a word much shorter than the difficult-to-understand 'troglodyte', but I do also like 'Beastly ignoramus, he's a total beastly ignoramus'.

Beast also conveys a sense of the superlative in itself (no modifiers needed) and of jokiness...

Beast
A person or thing that looks tough, ripped, cut, or has an intimidating presence.
Adjective Form: Nate is beast.

Noun Form: Nate is a huge beast.

beast
UK Slang- a person who is very good at something
He's an absolute beast when it comes to football.

Beast
Something that is very good, has exceptional qualities, is very large or just generally something that makes life more entertaining that the utter **** that it normally is.
'That is a beast' or 'what a beast'

Please see http://www.urbandictionary.com/define.php?term=beast

In fact, according to that page, the simple word 'beast' has many, many meanings.

Hope this helps.