Can I give my dog Bran-Mash?

I have a Bet hound who just got out of surgery yesterday. hes home and not moving at all but i bring him food and water he will eat his food but its only human food not his dog food. He will also reject drinking water. Im also a horse owner and i give my hoses Bran Mash some times. do you think i could give my dog bran mash so its food and he will get some liquids in him or can he not have watered down bran mash? and could i give him the horses bran mash or buy a dog bran mash?