his is still a baby. he probably fell out of the nest. the reason he cant fly yet is because his feathers haven't grown all the way in yet. you don't say what you are feeding him. try some parakeet seed and some millet sprays. make sure that you are feeding with dishes that are very low. try using a few tops to jars. hes probably not fully weaned yet. but will start to pick at the food. if he isn't picking at the food in 2 days bring him to the vet. someone there will know how to hand feed him.

hes to young at this point to even think of putting him back into the wild.

I do wild rehab on pigeons and have an umbrella cockatoo. good luck

My mom found this bird 2 days ago on the street and she said that it had been there for quite long time so she took her to a vet. And the vet said that it was healthy but still so young so that's why it can't fly yet. It barely eats and drinks but now it can fly and walk for a short time, but what do I do now? How long should I keep it before releasing it back to nature? And it seems pretty get used to us, so would it be cruel to send him back to the nature? I really loved this bird so I want to learn the best for it, thanks.