I had a foot of water in a safe from a hurricane induced flood. The water went back out within hours when the storm finally moved on. It still destroyed the furniture, appliances, flooring and sheet rock. After securing household item I got around to emptying it out. I was lucky as I designed my shelves so that my longguns were not sitting on the bottom of the safe, I had gi ammo boxes there. The guns were out of the water but the moisture still got on everything. Got some rusting. So I heavily oiled everything and moved my handguns to a bigger safe deposit box at my local bank and my long guns to a friends dry safe. Months later I finally got around to the safe and cut out the bad sheetrock, put a space heater in it for a day, scraped out the rust, repainted the steel, replaced the sheet rock and rebuilt the shelves. My safes have tumblers, never thought an electronic lock was a good idea. Im thinking that your friend needs to get an angle grinder and a lot of discs and start cutting.