Gr07. Depending on what type of Diabetes your friend has, it is possible to reverse it by change of diet, and if your friend is overweight, by losing weight by being on a sensible diet. It has been documented quite a lot recently in the Media. Contacting the BDA, or depending on where your friend lives, a Diabetic Association of some kind will help with advice, however I am assuming that your friend has seen a Dietician. Always worth checking the Internet for ideas and recipes for diabetics too.
I do not know if this will help, but this is what has happened to a close relative of mine, a diabetic, who has chosen to mostly ignore the advice. ( Forgive me if this upsets your friend, and indeed you but this is the reality of a type 1 diabetic who constantly abuses their diet ).
She developed an ulcer on her foot which did not heal. She had her toes amputated. Another ulcer broke out, and after being barely able to stand never mind walk because of the pain, she had a below knee amputation.
A while after this, her other foot did the same. The toes were removed from that foot too. Once again another ulcer has developed and she has been told that she needs this leg amputated too which she has refused despite being in constant pain and living on pain control which does not work most of the time. She is now wheelchair dependent.
Cataracts developed, as they often do. They were removed but because the damage was diabetic related, she is now blind in one eye. Organ failure is possible too, and I do not doubt that this will be the next thing.
I have lost count of the amount of hypoglycaemic episodes( dangerously low sugar levels) that she has had that have warranted hospitalisation because she has been in a coma.
Nothing and no-one will ever change her attitude to her diabetes. She refuses blood tests and indeed gets very defensive with her Doctor when he requests one because she knows what the results will be.
I am so so sorry Gr07, and indeed anyone else reading this post if you find it distressing, but it illustrates what can happen if you totally ignore this condition. I truly hope that your friend will be able to come to terms with this condition and as such live a long and healthy life.