@Ana-Dora , he can be fitted with a prosthesis that can give him 100% full function and mobility. Cost is an issue to be worked out, but hopefully he has insurance that will cover this.
As far as the diabetes is concerned, I'll ask what hasn't been brought up yet: How is his management of the disease? Does he monitor and control his blood sugar?
If not, given the advanced complications he's experiencing, this would be the absolute top of the list -- find out what's happening in terms of the disease, and take steps to correct if things are out of control.
If you all are deep into testing, diet, medications, etc. and trying valiantly to keep blood sugar in line, then managing the symptoms for best quality of life is where you should focus.
In either case, you've come to the right place. The family here can help with all of that, and give some comfort to. Welcome, we're glad to have you join our community... And we consist of both people with diabetes, and people who love and care for important people in their lives that have diabetes, like children, spouses, and boyfriends too
Again though, if you all are not on top of measuring and responding to blood sugar levels, that's your first and most important thing to do -- it could save a future amputation, vision, prevent a heart attack. It's very important, and we can help.