Wet automatic feeders?

So, My mother in law has a dog.

she's kept outdoors in a pen, and has a supply of dry food at all hours... but my mother insists on feeding her wet food, also, and doesn't like being even a few minutes late in feeding her. So, when she's running late coming home, she calls my very stressed and overworked husband and asks him to feed the dog.

This is a point of great aggrivation for him, for a wide variety of valid reasons, so I'd like to defuse the situation somehow.

I plan on trying to interject myself and tell his mother to call me instead, but in the event that that doesnt' work out, I'm looking for a more mechanical solution.

I know that they make 7 and 8 day feeders, that'll open at a certain time each day, etc, and I know hat they often come with coolpacks that'll keep food fresh for 8 -12 hours...

8-12 hours will work fine, but we only need to have one timer'd meal... is there anything like that that we can buy for relatively cheap?

Any other ideas? thanks.