Is it ever acceptable to use an exclamation mark following a question mark?
I am proofreading a novel and have been instructed to make no stylistic changes, only errors that impede sense/clarity. The copy-editing phase is complete, so if something is acceptable, I must leave it be.
At one point in the novel, one of the characters responds in an incredulous manner to a piece of information:
"Really?!" was her friend's reaction.
I'm not sure how much leeway to give to 'poetic licence'. The style of the novel is very traditional and the use of punctuation is conventional throughout i.e. not attempting any innovative or idiosyncratic use of language.
I know that most style/usage commentators would frown on the use of "?!' in formal contexts, but is it something a writer of fiction can get away with?
Advice from any experienced proofreaders would be much appreciated.