Can you give a 2 year old child versed in order to have his hearing tested reliably?

Doubtful: Versed is a sedative and an amnesiac so the person is sleepy and can't remember what happened. I see no value in using this to get a hearing test.

Which test: There are nerve reflex tests, which only tell you if the wiring is hooked up. These can be done when the kid is asleep. A true hearing test requires that the kid be fully awake & is determined by their response. For a 2 yr old this might best occur in a sound booth where tones are generated from speakers on different sides of the room.As the kid turns to the sound you get an estimate of hearing