Hello, thank you for contacting our service. 
Since when has his foot been hurting? How much does it hurt? Does he avoid or come out aggressive when you try to touch? 
I want to see a picture of his paw. 
I don't think it's broken like you, and it seems that he's hesitant to use his feet because of the memory of a sprain or slightly sprain. In this case, he'll start stepping back in three days.

Swollen back leg, does not appear to be broken but is not putting any weight on it. Limping but he’s able to use it to scratch his ear, shows no discomfort when I move it around.
Cause/treatment