Unrepairable Electrical Damage?

Sounds kinda fishie to me. The purpose of a fuse box in the car under the dash and the purpose of the fusible links that are usually located under the hood prevent your cars electrical system from frying up. Unless the was a bad electrical fire and burned all your wires you should not need to re wire your entire car,... How ever if your computer got wet (which is unlikely if there wasn't allot of water leaking in) you may need to replace that and that should only run a couple hundred buck. I would defiantly get a second opinion sounds to me this guys is trying to make some fast cash and take advantage of your mother. Best of luck to you.