How to troubleshoot/rebuild MacBook from liquid spill (water)?

I am rebuilding my partners 13inch Macbook Pro from water spill damage. When the accident happened she panicked and tried turning it back on which I believe fried circuits -logic board...however, how do I replace/fix the power button? the green light on power adapter doesn't turn on when I connect? is this a bad power button? can the battery also fry out from water spill?...it wasn't a lot of water but enough to fry logic board (which I am replacing)...what about the power connection?...anything helps guys!-thx