This is strange, if hackers actually wanted to donate those money, they would have kept it secret. It's clear that they had some ulterior motive - maybe they wanted to boost their own reputation or maybe they wanted to harm Bitcoin's reputation, or maybe the charities were the actual target?
Children International replied that they will not be keeping received Bitcoin if it is connected to hackers.
What are they going to do? Send them Bitcoin back or what send it to police

They'll probably give the coins to the police, who will try to investigate from whom these coins were stolen, and if that won't work, they'll probably auction the coins.