Hi,
I'm 72 year old male with similar problems. I'm T2 and have had high glucose levels for many years. I'm now on insulin with acceptable glucoes levels. But any damage has been done and cannot be undone.
I have been developing a problem of being unable to naturally empty the bladder. I have a slightly enlarged prostate which is of little concern to all.
I have the urge to pass urine but the signal to the appropriate muscles to empty doesn't happen leaving me waiting for gravity to help or my physically having to squeeze out the urine.
Every test I have undertaken has come back within acceptable levels. After a quick trip to ED for another reason and linked to ANS in hindsight and 7 hours latter the Dr discovered I have Autonomic polyneuropathy. Neuropathy is common amongst diatetics, the poly meaning both the 2 main nervous systems are affected for me. That is the usual neuropathy diabetics can experience in the limbs and the Autonomic neuropathy being main organ control system of the body.
With any luck your father doesn't have such problems but I discovered few if any Dr's know about auntonomic polyneuropathy or even understand it. That is why it has taken so long for a diagnosis, it not being on their radar.
It is debatable what caused it for me but there is no doubt diabetes hasn't helped it.
So this give you another disease you can ask to be checked for.
I have my fingers crossed it is not the cause as it is a disease with no cure or treatment and can eventually wreak your life.
Cheers