What can I do to check for water damaged parts on Sony Vaio laptop?

Water (or any liquid) will usually leave a noticeable residue. Check under the keyboard and anywhere else for signs of prior wetness and any remaining water that might be present. Having used computer-cleaner spray, this might be a little more difficult, but shouldn't be a big problem. It depends on how deep the cleaner got.

As you dismantle it, assuming that's your plan, look for any discoloration of the PCB and for where residue may have built up. I've seen wine, coffee, and water (residue) cause problems, but once cleaned off, the systems worked fine. The lone exception was, with the coffee situation, the battery-charging chip was completely covered in coffee, had overheated and burned out. The rest of the system was fine, fortunately.

I generally use electronics-safe distilled alcohol with foam-covered-cotton swabs and a toothpick (or other small, non-metal implement). Don't use metal unless you've got a REAL gentle touch. It's insanely easy to flake off layers of silicon with metal tools. More so if there's heat damage. This is a bad thing. (I know from experience.)

Obviously, I make no guarantees, but this is based on my own experience fixing various laptops.

I hope this helps!