My Sister Is 65 And Has These Lesions On Both

My sister is 65 and has these lesions on both of her legs the left leg has actually lost tissue bulk. Her doctor treated her lesions with silver nitrate and the lesions have gotten far worse. She is diabetic and he won't prescribe a steroid for obvious reasons. What method may be something to mention to him for a diabetic and suffers with Rheum Arthritis. I am worried she will have to have her leg amputated and we must try everything possible to heal these things. Any thoughts