My husband is showing signs of early dementia but will not acknowledge physical or mental changes. Will not discuss issues with his doctor and makes me look foolish if I mention anything during his appointments. There have been many changes over the last couple of years and seem to be getting more pronounced. I try to make a note when I notice something significant. Yesterday he told me that something is going on with his eyes, that sometimes he can’t see color. He said images were dim, more like black and white. When I asked him later he fluffed it off and wouldn’t discuss.
And so when my husband would go in and his neurologist would ask him how things were going and my husband would reply "fine," the Dr. would know better and be able to address the issues at hand. It worked well every time.
Contact his doctor(s) any way you can to let them know what's going on, as someone has to be looking out for your husband since he won't.
Wishing you the best.
Fax or snail mail also work. Make your communications concise and bulletin, i.e., "I am very concerned that John is reporting loss of color vision and doesn't seem to think he should see anyone about that."
I would send a fax or email before each appointment you go to so that the doc is alerted in advance about your concerns.