I tried this back in school before my deaf alarm clock. I was suprised by the noise...the way the bed creaked whenever I moved, the cars whooshing by my window, the murmer of sounds outside my bedroom door...I had no idea how hearing people slept. It also never worked, using the alarms and keeping my hearing aids on, I slept through them, I think...and I woke everyone else up. I don't think it's a particularly good idea, CI or HA. Bed time for bed and out goes the HA. If you're concerned about your son, there's good technology out there for that to help you and it's more reliable than leaving your HA or CI on all night.
Laura