Fledging of bulbul with lifted off ground leg.

I recently rescue a 5 day old nestling of yellow vented bulbul which the parents did not return after 12 hours in my garden,it kept making noises and I observe from afar there haven't been adult birds.I have fed it diligently with frozen blood worm which has been thawn together with puppy food and tropical fruits mix with wheat germ,pounded half my calcium tablet into the puppy food once.It's now a month old and has grown into a healthy fledging,making short flight perching on my shrub in the garden,also walk with a normal gait on the ground,even fly towards me upon hearing my whistle.Still hand feed it with worms,fruits and wheatgerm.
Yesterday I left it indoor while I went out for a few hours.When I return it was perched on my home furniture.Since then,I notice it only uses one leg while the other one is slightly lifted up on non-weight bearing,it's trying to compensate by using its wing to perch and walk.Upon inspection,the fingers of the affected leg refuse to grip and limp looking although the alignment looks fine,doesn't look dislocated or sprayed,just non-weigh bearing.My guess is that it must have substain the injury from a fall while trying to fly high.There is no avian vet around.I very worried,pls advise.Carrie from Kuala Lumpur,Malaysia.