My very dear Nick and Louise,
Thank you very much for your kind email, I am sorry for the long delay in replying. According to my divinations it would be best for your son to take Tibetan medicine and to see a Tibetan doctor.

I have found that the most effective thing to do for diabetes is circumambulating stupas and holy objects. You can set up a table with holy objects the same way as when you perform animal liberations, and then circumambulate it. Set up a large table full of holy objects, statues, stupas, scriptures, pictures of Buddha, etc. It is most important that the stupas have the four powerful mantras inside (like the stupas we make in my house). If you do not have any stupas that have the four powerful mantras inside you can ask my attendant to send you some. Then, your son and the whole family should circumambulate the objects as much as you can. The best would be five hours a day, but if that is not possible, then as much as he can. He doesn't have to constantly circumambulate it, he can have many breaks.

I am also making prayers for your son. Please make your life most meaningful with the thought of bodhicitta.

With much love and prayers...