Welcome to HCM
Your father is having DIabetes
which is controlled by taking actrapid insulin
,after going through history of your father he has developed mild kidney failure that is why blood urea and creatinine
level are high.
It may be due to complication of diabetes called nephropathy or some other factor causing deteriration of renal function,such as analgesic
use or infection to kidney.
A urine analysis report is required to know infection and amount of albumin lost in urine.
of KUB that is kidney to know size of kidney is very useful.
Get all investigation as soon as possible to treat treatable causes,avoid analgesics(Pain killers)
In the mean time take low protein,low potassium,and salt restricted diet.
Take care of your father
Good Luck to you