Powerbook Screen Problems

He shouldn't be turning it on and off. He should let it sit for a while till the liquid goes away (since i bet the liquid got into the mobo via the kb, but idk i don't own a AL). Anyway long story short, i bet he shorted the mobo.

Drain it and use a hair dryer do not try to turn it on

if it was just water let it dry. however, it was a drink with sugar or other stuff, the best method would be to wash the logic board with water and let it dry completely. also clean all the connection between the LCD and the logicboard. however, my guess is you didn't get much on the logic board and it more has to do with the LCD getting wet. either way, if you turned it on when it wasn't dry you probably fried it.