“Older than” is a variable term. 2 months? 2 years? Ten years? Who we have to worry about are the shadchanim. A year or two is irrelevant, so make sure the shadchanim you consult know it. Same with height. Why does the boy have to be taller? In Europe it wasn’t a issue. An inch or a few? So what.
It strikes me though, that the OP’s friend may have some issues. Is he looking for an older girl because he’s got a “problem” and he thinks that an older girl will care less? Or that her “desperation” will give him more power?
It’s like blue for boys and pink for girls. It wasn’t something that existed in Europe, but we’ve picked it up from the non-Jewish environment here.