No chance before May 24th by sea. Takes 6-8 weeks normally.
I'm sure they will be just as grateful to receive such a gift...even if they have to wait a little longer.
You could always send them some cash through Western Union, so they can buy their own supplies locally.
That would take a matter of minutes, and there are collection points in every town in the Phils.
Locally sourced school supplies are very cheap there . (I know, because I used to have 3 kids in school in the Phils).