Hi XXXXXXXXXX,
Thanks for posting your question on justanswer.com. It is a good question. There is no doubt that the best healing of the cockatiel's broken leg would be accomplished best with veterinary intervention.
In the absence of this, it is possible that the bone will heal incorrectly and cause a deformation of the leg. The best thing that I can recommend is to place the little guy in a smooth sided enclosure (so he can't try to climb up the walls) and keep him on a smooth flat surface for 6 weeks. Keep his activity limited to allow the broken bone to heal better. What works well is a deep rubbermaid container, or an aquarium for these situations. You want to place his food and water in shallow disshes on the bottom of the enclosure so that they are easy to get to. Make sure that he is consuming a good diet with fresh veggies and plenty of calcium so that he can heal as quickly as possible.
Again, this is not an ideal situation and I recommend if at all possible, your friend should take this little cockatiel to the vet for proper fracture repair. Good luck, and let us know how he does!
Dr. Kris
Avian Veterinarian
DVM since 1992, Member of Assoc.of Avian Vets. 1992, co-Medical Director for The Gabriel Foundation