أَتَضْرِبُ زَيْدًا وَهُوَ أَخُوكَ؟
Are you striking Zayd when he is your brother?
Interrogative hamza may be used to challenge an act presently occurring; it does not impose the same prospective reading on the imperfect as hal.
If the speaker is rebuking the addressee for what is happening now, this construction can suit the intention better. The student must still distinguish the primary interrogative sense from the rhetorical move of rebuke or denial.
ConstructionTime/focusResult
Hal taḍribu Zaydan?Usually prospectiveFuture question
A-taḍribu Zaydan?Present or future by contextFlexible
A-taḍribu ... wa huwa akhūka?Present act questionedCan convey rebuke
Hal taḍribu ... wa huwa akhūka?If meant as present rebukeTension with hal’s usual reading