When we say They are brothers or they are best friends and we want to make a wh question is this one correct: "what are they" I want my answer to be brothers or best friends. Thanks
The only problem is that there's a risk of ambiguity: you might get the answer 'They are hungry' or 'They are Chelsea fans'. To avoid that (probably, in practical terms, slight) risk, you could ask 'What are they to me?'.