The very most is warning. No action yet, police cannot do
further than a warning or monitoring his fb and phone line.
Not true, under SG law, the police can charge him in court. There
are actually similar cases where Singaporean are charge in court
and jail for similar things. However as I mention, he is study in
International School which mean his parents are well do to FT, thus
I believe he will get away with a warning only.