It's not an official medical term at this point; but it's been proposed by some researchers. Quoting from MayoClinic.org:

"It's an accepted fact that people with Type 2 diabetes have a higher risk of Alzheimer's disease. One reason may be reduced blood flow to the brain because of damaged blood vessels, Dr. Bu explains. "And, therefore, the supply of essential nutrients to the brain is also impaired."

"Dr. Bu has found genetics may also be to blame. A variant of the so-called Alzheimer’s gene, APOE4, seems to interfere with brain cells' ability to use insulin, which may eventually cause the cells to starve and die. Unofficially, it's called Type 3 diabetes. "What it refers [to] is that their brain's insulin utilization or signaling is not functioning. Their risk of developing Alzheimer’s disease is about 10 to 15 times higher."

Here's a link to the article I'm quoting from:
https://newsnetwork.mayoclinic.org/discussion/m...

Im not sure. He was diagnosed as borderline type 2 for many years. 2019 it was full blown and been on metformin since then. That's when he received disability for it. No one in his immediate family had ever been diagnosed with it.

Could that include Type 3 with Alzheimer's?

VA recognizes exposure to Agent Orange causes type 2 diabetes in Vietnam Vets

Answers some questions alright! Hubs diagnosed with stress caused diabetes 25yrs ago. Who knew!!