I'm sorry to hear. I live in a flood prone part of the world and I have lost machines because of flooding.
I have also successfully restored machines that have been underwater. It looks like you are on the right path to addressing the issues. So long as you can get in quickly and clean everything you should be okay.
I also recommend getting your hands on an ultrasonic bath if you can. Also, getting contact cleaner on wiring connectors early will be important.
For any metal surfaces that need extra time before fixing, I recommend using Inox to coat these parts until you can get to them.
All the best to you and your friend. Flooding sucks.