If the resevoir is low (& chances are its been topped up) then I suspect that your friends brakes are down to the metal, which can make them overheat, expand the piston & bind themselves to the disc.
As for the rear brake (which wears faster than the two front pads) is probably in a similiar state, with little or no meat left on em. The rear brake always feels weak when you don't use them in tandem with the front.
Either way, he needs to pull his finger out & get stuck into some brake maintenance, new pads & fluid. With a bit of luck this could be the only problem.

 

I have no idea what shape the pads are in, but my buddy called me a little bit ago. He said both the front and rear ARE locked up.

 

What Tacoma was referring to with the stuck piston is the thing that pushes on the brake pad. The piston is generally an aluminum cylinder. The brake fluid fills in behind the caliper piston and forces it outward, pushing the pad onto the rotor. In older bikes what will happen is moisture will get into the brake fluid and corrode the piston. Then when it moves in and out it'll get hung up because the aluminum will become pitted.

My diagnosis? I agree with Pacemaker. What probably is going on is that the pads have been worn so far down that the piston overextended itself and became unseated or seated crooked inside the caliper. I'd take the calipers apart, pump the lever until the piston pops out. Inspect the pistons and look at the brake pads. My guess is the pads are shot. Just pop the piston back in and bleed the brakes.

 

... Dunno how I gotrecommended for this job. We had the 60degree day today... but no, the bike has to be fixed when there's a high of 37degree's tomorrow.

I guess I will pop off each caliper and take a look at the pads and see what kinda action I can get out of'em tomorrow. I have spare 954 pads, hopefully they'll fit his bike so I can get this over with.

 

929 and 954 pads are the same.

 

I went over to his house tonight and looked the bike over while there. The pads are in okay shape, not worn down to metal or anything, no wear on the rotors. Yes, both front and rear pads are locked up. I released the valves on each caliper and loosened thepads up... brake fluid immediately oozes out, so it's getting juice. Seems like it's a bad brake line, but front and rear went out at same time?