My uncle passed from renal disease. Months before he started withdrawing. A counselor said to me it sounds like a form of dementia? True?

So sorry for your loss. I understand that you are reflecting on his life. You’re grieving and thinking about what happened during his lifetime.

Sometimes, we find answers to mysteries and other times we don’t. I wish you peace as you mourn the loss of your uncle.

According to your profile, you're caring for your mother who suffers from Alzheimer's/dementia, so you're familiar with what it looks like. Did your uncle exhibit any behaviors your mom exhibits?

My dad declined cognitively as his ckd got worse, too.

End Stage Renal disease can effect cognitive function.
It can lead to cognitive impairment and dementia.
BUT I would not say the primary diagnosis would be dementia the primary would be ERD.
End Stage Renal disease can cause other symptoms as well and one of them that I found is depression.
Depression may have been the cause of your Uncle withdrawing and not cognitive impairment or dementia.

I am sorry for your loss.

We didn't know your uncle at all.
If dementia is present there would be a GOOD NUMBER of other indicators.
Withdrawal can happen with simple exhaustion, and passing from renal disease, like liver disease, leaves one extremely exhausted. The normal "social flow" would be impossible.

I cannot, quite honestly, imagine why you would want, now your Uncle is gone, to spend a lot of time on whether or not he had some dementia, because this cannot now, at this point EVER BE KNOWN. There was apparently no testing. So this is simple guesswork.

My condolences on your loss of this gentleman.