Last week my dad tripped over something and broke his toenail, and a few hours later it suddenly popped off. (Not all the way though, it was still connected at the bottom). So he kind of pushed it back down and my mom covered his toe in band-aids.

Will the toenail stick back to the toe on it's own? Or does he have to pull it off and not have a toenail?

What do we do?

It will eventually fall off and grow a new one. He can cut the broke part back S0ME with a nail clipper if it is too annoying.

So should he take the band-aid off and let it fall off?

It will fall off with the band aid on. He should just keep checking it when he changes the band aid. It will be fine! :)