In this case, it's always have. "to do" + [any verb] directly will always leave the verb in infinite form I think. You would never say "he did had." Neither would you say "he does has." It's always do+have. The conjugation of the word "do" will take care of the tense ("did have" - past; "does have" - present; "will have - future). So, for your question, you would say "he did have", or "did he have...?" in interrogative form.
as for "brothers and sisters" vs. "siblings", either one works equally fine.