Feeding/saving green tree frogs?

My brother found a puddle on my parents farm 2weeks ago that has half grown tadpoles that were baby green tree frogs. Knowing the puddle was drying up he collected alot of the tadpoles about 200 of them. Well now they have turned into the most gorgeous tiny green tree frogs.
He went back a few days ago and the puddle hardly had any water left and there were about 3inches apparently of dead green tree frog tadpoles on the top. He saved as many alive that he could. So now he has around 200 tiny babies that have lost there tails and turned into little frogs. And another 100 or so tadpoles with legs.
The problem is he can't let them go just yet as they are so vulnerable but he is worried they are hungry (and some look skinny to me but very healthy) he is feeding them mosquito lavae but the bugs he gets are too big for them. We don't have any sort of WIRES around here due to the distance we are and have no idea what to do with them all. They want to release them on the farm once they are out of this danger zone but how does he look after them to ensure they remain healthy and feed them enough or who takes them to ensure this happens and for them to be released in an environment where there are quite a number of them living? My parents farm is ideal as thats where they are from and we have always had large green tree frogs so we know the environment is right.
Any suggestions I can pass on would be greatly appreciated.

Just about the only thing I ever remember Don Burke saying on Burke's backyard is if you want frogs in your pond, stick one or two of those small solar lights just next to the water. The light attracts insects at night, which fall into the water - instant food! Worth a try for a night or two and observe what happens?

Thats a really good idea. I'll let him know. They have solar lights. They are on a verandar so the flies, bugs etc would be limited but they could open doors etc windows which might attrack them to come in with the light.