First thing is to stop the bleeding. She can hold pressure on the area if she can find where the blood is coming from. Is there anyone there with her who can hold the bird wrapped in a towel? She may be able to use a small stick like a popsicle stick, cut to size, and wrap the leg with cloth or gauze bandage.
He must go to the vet as soon as possible even if she does a good job. Birds go into shock from dog attacks. He may need medication.
Tell her to take all perches out of the cage and pad the bottom with towelling then put a lamp nearby to warm him up. Don't let him overheat but do let the temp go into the mid 80s where he is. Be sure he drinks. She can put a flat dish on the floor with food and one with water.
Please come back and let us know how he does.
Best wishes,
Annie