Question: can you counter avada kedavra?
Answer: There is no counter curse to the Avada Kedavra (Expelliarmus only worked for Harry because his wand was twined with Voldemort's and could not be forced to do battle with each other). ... Avada Kedavra can be dodged. It can be blocked physically or with spells. But once it hits you, you can't stop yourself from dying.