Cheryl,
My late Dad had Diabetes.
He died from it because, it also causes a TON of other health problems in a person. It compromises their entire health.
Ultimately, you CANNOT control, a body's every minutia of responses. Even if a care-giver is diligent. The person themselves, ALSO has to take care of themselves. If they are able.
Also, per age, if a person is elderly, they have a hard time... "managing" themselves much less their health and condition... because, it is a lot to manage and remember. DAILY.
EVEN if someone takes care of themselves... it can really spiral and get worse... and/or other health problems arise.
My Dad, had type II Diabetes. He saw the Doctor regularly. My Mom AND me/my Husband, took care of him. And we did it well. But, Diabetes weakens the whole body. It is not only watching their blood sugar levels.
My Dad, REGULARLY, saw a Renal Doc, a heart Doc, his Internist, a specialist Eye Doc that specialized in Diabetic eye problems, etc.
But my Dad, due to Diabetes, had: heart problems, circulatory problems, eye problems, and his Diabetes.
Then... he had a stroke.
No one could predict that.
He also... had Renal failure... and was on Dialysis.
No one could predict his kidney failure, either.
I really hope... your Mom... does NOT feel "guilt" over this.
If she does, please.... tell her about me and my story about my late Dad.
It is not, her fault.
It is not his fault.
It is a difficult, disease. Insidious.
It takes the ENTIRE family... to care for a Diabetic. Especially, if they are elderly.
We even had to fit our home, with guard rails both outside and inside the house and in the bathroom. Because, my Dad was not well balanced on his feet. Even pre-stroke. And not just due to old age. He was not old.
My Dad, also did regular testing of his blood sugar and exercised.
Sorry, I have to run... but hope this helps.
**Okay adding this: It took my entire family... to do care-giving for my Dad, in his condition. It is really really hard.... for just 1 person to do care-giving. Because, it is 24 hours a day, everyday.
As I said, I really hope your Mom does not in any way blame herself for this, nor that other family members may blame her.
Hugs, and for her too and your Dad.