To expand a little on Bob's post, as someone who's taken apart more than my fair share of unibody MBPs...
Best case scenario here is he needs a new top case -- the keyboard is an integral part of the top case on unibody models -- which won't be all that cheap, since the unibody models are built upside down compared to pretty much every other laptop model out there. The top case is the starting piece upon which the rest of the laptop is built. Figure probably $200 for the part, then another $100 or so in labor for someone to rebuild his laptop inside the new top case.
If the unit **** off when the syrup was dropped on it however, that doesn't bode well. That corner of the unit is where the magsafe board and LVDS connector is, so he could easily be looking at a new MLB and display assy. At which point it'd be cheaper to just buy a new unit. Apple is extremely uncompromising (more than usual) when it comes to any kind of liquid damage, and it is absolutely not covered under any warranty they offer.
And given the way the unibody models are designed, you need a special positioning block to align the display hinges, so it's not like it's the sort of thing you can just do yourself. You can find the positioning block third party, but it's about $50-$60, and you'd probably only use it the one time. So you wouldn't save that much if you tried to do the repair yourself. It would also could make a big difference if this is a mid-2010 or early 2011 model if a MLB and/or display assy is required. Use the wrong part and you could end up compounding your problems by destroying your replacement parts.
Now, if you want to try and figure out whether it's just the top case or the MLB you'll need to remove the bottom cover, disconnect the top case flex cable, and short the MLB power pads. Where they're located varies by model, so again you need to know if it's a mid-2010 or early 2011. If the unit turns on without the top case connected, it doesn't rule out the MLB, but it's a good sign. If it still doesn't turn on, then just start pricing new laptops.