Great Kelly, glad my thought agrees with you!
Just a reminder, the little indicator lights on the stove may be 220v. (the one on my stove was) so your B-I-L will need to account for that.
I'd just hang the female half of an extension cord off the back of the stove, [if he's not going to screw a metal box and a regular "switched" outlet onto the back] and wire the light/lamp of the range-hood via a regular extension cord. Let the fan be powered as is!
Another thought. Have a wall-switch timer (say one or two hours max) engage a relay that turns the power to the the entire stove circuit on and off. In theory it could also be done in 24v (Class 2)wiring, making life simpler. Class two wiring is like a low-voltage doorbell or telohone. Such plastic-sheathed wire can be left exposed, and/or surface-mounted.
In that case, I'd disable the stove's clock and leave it set for noon/midnight so as not to confuse mom.
With my ex-partner's grandmother, the gas to the stove was shut off so she could not try to cook. Eventually she just figured her stove died and there was no money to fix it. Since there was another one in the house, she was fine with that. She never knew her husband was using that very same stove. [this post was last edited: 5/28/2010-11:20]