I would try and remove and salvage as much as possible from the movement side first, then let what cannot be removed sit for a few days in a shallow dish of rust remover, with the fluid level just below the edge of the dial. Then see if you can gently pry the dial away. Who knows, you might be lucky and not have to get medieval on it's ass. If that doesn't work, I'd try to drill the screws out with the aim of leaving the feet intact, maybe again in combination with rust remover.
It looks really bad, but maybe one or two bits are good for spares. The dial and hands especially have come off lightly and look good, considering.
I think your daughter's friend owes you a beer.