First off, he needs a vascular workup and an angiogram, if the workup shows that there are adequate blood vessels, then a bypass may be in order, but a foot is not always able to be saved. The other thing is to get involved with a wound clinic that has hyperbaric oxygen, sometimes this treatment will aid in the salvage of a foot. I have not seen what the foot looks like and there are times when only amputation is the correct treatment, if the infection is too extensive. The problem with diabetes is that the small blood vessels are destroyed and the foot is numb and the damage/infection is usually sever before it is discovered the key to foot salvage is oxygen delivery to the foot and control of the infection.
I wish you luck with this, but start with a good wound clinic or a vascular surgeon.
I hope this information is helpful. Good luck dealing with what I know is a difficult situation. Let us know if you have additional questions.
Richard Graves, DPM
The benefit is that a foot amputation takes care of the infection and affords healthy tissue time to heal.
I suggest you discuss with the surgeon.