We can look at it like this: kidding and hyperbole aren't bad grammar. Limbs could literally be worn to the bone; that they are actually not isn't a matter of grammar.
The character is fictitious in the first place, so we could argue that "his looks were haggard" is misusing the word were, since were may only refer to a person that existed. :)
The character is fictitious in the first place, so we could argue that "his looks were haggard" is misusing the word were, since were may only refer to a person that existed. :)