your friend shouldnt off it.. he should take the battery out even tho phone is on..

if he press off.. sure die~
my friend did the same thing actually..
we went to barbecue party and ppl end up playing and splashing or literally pouring buckets of water to everyone
my friend is the unlucky 1.. whole bucket of water from tip to toe~ me, on the other hand is the sole survivor  not even a drop coz i ran somewhere far 
she went home and the phone is actually still on..
but she didnt know the steps to safe a hp n switch it off.. 
she told me the next day her hp cannot switch on.. n i ask for details then i told her what she did wrong~
if she ask me in the first place.. her hp might still b functioning now..