There may be a fracture. If the bird will let you touch it, you can look and very very gently extend the wing. If there is any struggle whatsoever, do not try it yourself. It is possible that the shoulder has been injured, and struggling could make it worse. The treatment is to confine the bird and prevent any flying for minimum 3 weeks.The problem may involve internal injuries, often caused when children grab a pet bird.
Move the bird to an aquarium, box or carrier with soft towels in the bottom, no perch, and food and water in low bowls that he can reach easily. Put the whole thing on a heating pad on low or medium. Keep him partially covered, warm and quiet.
Do not try to force food or water. You can offer warm cooked rice, pancakes, cornbread, grapes, melon, greens in addition to normal food. Transport as soon as possible.
Pet/feed store medications and home remedies are harmful, ineffective, immuno-suppressive, and make them much worse and may interfere with the veterinarian's diagnosis and treatment. Do not use them.
He needs to see an avian-experienced
veterinarian ASAP for complete examination, diagnosis and appropriate treatment. Check the link http://www.aav.org/association/index.php?content=activeMembersList
for members of AAV in your area or call your regular vet and see who they recommend; ask if they really have worked with birds a lot.
He may need injectable pain medication and many other medications. Act quickly and good luck