Do you have much of a history on the car? Have either of the master cylinders been replaced? If the brake pedal is firm when your helper is pushing it, I'd be sure you have a plugged line. I can't think of any other way that fluid wouldn't get to the brake, unless it's leaking out of the system somewhere. Sometimes a master cylinder will leak internally too, into the brake booster cavity. If you have a lot of miles on the car you might think about replacing that master cylinder just for peace of mind.
Does the clutch work? I've noticed a few times that a good clutch bleeding really changed the feel of the pedal. Most times it hasn't though. If it's not working, start thinking about a new slave cylinder.
You could also unscrew the bad caliper's hard line from the ABS pump, get a catch can under there, and see if any fluid is coming through when the pedal is pushed down. Blow downstream through the line toward the caliper to see if the line is clear. I hope you don't have a plugged circuit in the ABS pump itself.
I've heard of a few times that the ABS pumps were clogged by forcing fluid backwards from the calipers during pad changes. I've never seen that myself...and overhauling ABS pumps is not something I've ever been tempted to do.