Just try a 30C and see how she reacts.

Incidently a good specific remedy for weak ankles is Strontium Carb. It is people who are always going over on them.
Does your Mother still have any residual pain from the broken ankle?

I normally prescribe Calc Phosphate Tissue Salts ( Cell salts) to be taken concurrently with Symphytum for fractures to strengthen the bones. I am aware that others won't approve of this but as I say , it is what I do!