is a very complicated disorder as it remains asymptomatic for years. And when the person get to know about it, generally its very late. The major complication of diabetes is the Neuropathy and Nephropathy which leads to very fatal results, Although it affects every system of the body.
As your father is 65 years old and already on haemodialysis, very few options are there.
I have treated few cases like this through Homeopathic
medication. But for a better treatment I need a proper case history of the patient.
In your case in my opinion you can try a homeopathic medicine "Phlorizin-200", it is a rare drug, But I have got miracleous results with the remedy. Only 3 doses with an interval of 10 minutes each are sufficient. And also use Phos. 30 along from the next day, twice daily for 7 days. U'll yourself see the difference.
Keep me posted about the condition of your father.
Also keep following the various diet and regimen as suggested by your Doctor to control the sugar level, and continue dialysis till his condition gets better.
Wishing a better recovery for him,