هَلْ تَضْرِبُ زَيْدًا وَهُوَ أَخُوكَ؟
Are you striking Zayd while he is your brother?
If the speaker intends to deny or challenge a blow currently being dealt, hal’s prospective orientation clashes with a present-time reading supported by the context. This is why the cited configuration receives criticism.
That criticism is not a claim that the words are meaningless in all imaginable settings. It concerns a particular present-denial interpretation; a different future-oriented context needs its own analysis.