A general surgeon asked my mom to apply a mixture of glycerine and mag sulfate to her lower leg.?

I suppose the surgeon is right.

Magnesium sulfate, otherwise known as Epsom Salts, has been valued for many years because of its diverse benefits. Rich in both magnesium and sulfur compounds, Epsom salts and Epsom salt soaks and baths have been used for a multitude of different situations.

Beside I remember a neighbor of mine using a product quite similar to the one in your query. It was called the Kirkman's Magnesium Sulfate Cream.

the glycerine keeps the skin on her legs from drying and cracking due to the edema caused by the cellulitis, and the mag sulfate is a natural bacteriostatic agent, to prevent further infection.

I think the answer of "Sharada" best fits your query, though I have never heard about the Kirkman's cream.

Absolutely it works! Tell her to be patient. It takes time.