My former sister-in-law's father had a similar problem. The circulation in his leg was so poor that medicines/antibiotics could not get to the non-healing area.That looks like a pretty good way to take care of the problem, what with the poor circulation and all.He decided to inject or apply medicines directly into the bad area. He did the treatment himself. I'm not sure, but he may have opened up some of the area so he could apply medicine directly to the tissue.
I gather it was painful, but it healed the problem area and avoided or greatly delayed amputation.
It's a similar problem to what Jim has.
I'll bet if he knew of this approach he would have tried it!
It’s called a fasciotomy. I can’t believe you are giving medical advice here. Leave that to his doctors who have actually examined the leg. Please say a prayer or wish him well instead.
Best wishes to you Jimbo, family and friends.