Tear Down & Rebuild of Hydrolocked Engine?

I drove into water during heavy rain very slowly. The car shut off. I pushed it out of the water. The interior was not wet. Had it towed to a repair shop. First thing he does is try and start the car. He told me it was hydro locked and he needs to pull the spark plugs and drain it and it should be fine and told me to come back in 3 hrs. After leaving it sit there for 7 hours he finally started. Said there was a ton of water in the engine and it still wouldn't start so I need a starter. After he put that in he tried to start it repeatedly and it did finally start. He said come back another day to get the plugs and wires replaced (when I had more money) He was really rude to both me and my wife throughout the day. The car was barely running. He didn't even change the air filter and it was soaked and molding when I looked a couple days later. The check Engine Light was flashing. My oil pressure is low and the temp went up to the red. One of the spark plug wires was ripped and lying on the engine and another spark plug was not completely in place. The car is not being driven. I have seen what is generally done after hydro lock. This guy is a nightmare and a bully on the phone and a bully. He made many racist comments towards me and called me some vulgar names after many phone conversations. I'm going through the proper entities to get the repair costs covered. I wanted to confirm that this engine needs to be either replaced or tore down to see what damage there is. I'm hoping for a rough estimate to diagnose and fix all this damage.