delayed Liquid Damage, some times turning on sometimes not

I have MacBook unibody, I spilled some tea + sugar on it. it turned off and then turned back on the next day and was fine for a week. I gave it to some guy to open it up and clean up the residues with isopropyl alcohol and let it dry. after putting it back together it would turn and it wouldn't turn off, after turning off by holding the power bottom it wouldn't turn on and it would turn on again after a while. the light indicator on the front stays on.

after consulting with many people these are the possible causes:

1-damaged nVida GPU --> logic board change

2-damaged topcase

3-damage in cables connecting to logic board

4- SMC needing to be reset

What do u guys think? where do you think is the damage?