@theseaisbrightfromhere that's kind of you to want to support the charities. There are small volunteer groups who help the boats when they arrive and ensure people don't drown. One is called the lighthouse.
But probably best is Msf who are the only ngo at the camp doing anything worthwhile
In terms if an answer... It's so difficult to know. The Greeks don't want to allow a huge permanent settlement on lesbos because they know if they do Europe will keep its borders closed. In Turkey there are 3 million syrian refugees
The vast majority of Syrians are in Turkey and Lebanon. Not Europe. But Turkey and Lebanon are poor countries and Europe needs to take a share of people fleeing war.
Personally having seen it first hand the thing I found beyond belief is the lack of proper shelter and medical care. There is just no excuse for it. European countries need to start large scale resettlement and relocation in order to support the Greeks
People I met had tried to stay close to home. Syrians for example had left their cities to villages then left the villages for camps on the border. Each time violence followed them and they were pushed forward again.
And ultimately to stop this crisis we need to fight for a world without conflict. And that includes stopping our governments supplying weapons and arms around the world.