Embden Gander Hit by Car, PLEASE HELP

My Embden gander (Clarence) was hit by a car 2 weeks ago. He hasn't been able to walk since. His "good" leg seems okay-ish but he can't walk on it either. I think he put his weight on it and strained it as well (as the other leg that was hit does not work at all). The bad leg is swollen badly at the ankle and he acts like he can't use it at all. It is floppy but warm to the touch. He has been to the vet 3 times. They say it is not broken. They give him pain killer with anti inflammatory and antibiotics and say to give it time and bring him back in a few days (every time). He has been for swims in the pond but hardly uses his bad leg at all. He just goes over and sits on the side area and rests. He sits in the same spot all day (on land) and isn't hardly eating at all. I am worried sick. I feel like he should be healing or making some sort of improvements by now (it has been 2 weeks) but he is not. He can flop himself with his wings about 4 feet but that is it and he only does that once a day. Does anyone have any suggestions that I can do to help? Please tell me he is going to be okay . He is only 4 years old.

 

Sadly my boy Clarence gave up and passed away. He is missed every day.

 

Thank you so much.