brakes aren't working

Sounds like your master cylinder has failed from sitting and somehow the piston seals have shrunken, or you have air in the system. I'm thinking 'air in the system'. Was the brake fluid really low? Check for a brake fluid leak which could have drained the brake lines and drawn air into the master cylinder - you're pumping air - therefore no resistance in the brake pedal. If the fluid was low because of a leak, it could be from the master cylinder (pull up and inspect the carpeting for wetness, under where the brake master cylinder connects to the brake pedal through the firewall). Look at all the inner sides of all the wheels for brake fluid dripping from the brakes. Look at the rubber lines connecting the hard steel lines to the brakes at the wheels.