My husband has cognitive decline. It's not ALZ but he certainly is slowly leaving the person he was behind. It's accelerated a lot over the past 6 years, since he lost his job of 27 years during Covid. He's 73, soon to be 74. I am 71. He has diabetes and recently is craving sugar. I think it's a dopamine rush to his brain. Our son who is 48 knows too but his brother who lives in another country is not aware that he has dementia. Well, he might but doesn't ask me much about it. His brother and brothers wife are both now 80 years old. Their son committed suicide 6 years ago and they have their own problems with that. I know I feel grief for the husband that I used to have. I want to make him feel safe with me but he continually talks about the past as if he could rewrite it just by talking about the what if's. My patience is wearing thin. We have no friends as a couple and I find it hard to find friends at my age. Women who are married tend to already have their own circle. It's just hard to find friends without looking needy. So I am kind of alone with my grief, the grief of my husband slowly disappearing and am now turning to forums like this for support.
People need to know in order to help.
How do you know it's not Alzheimer's? Because of your theory about diabetes, sugar cravings, and dopamine rush?
Your husband's case appears too complex to diagnose on your own. Please consult husband's doctor and get doctor's opinion.
My friend's diabetic husband was recently showing cognitive decline, and his medical team discovered that he had fluid in his brain cavities. The fluid was drained in a fairly simple procedure, which is supposed to help him regain cognition. This only happened a week or so ago, so I don't know the full outcome. But if your husband were my husband, I'd certainly keep him in touch with his doctors and make sure he's tested for any condition that could be affecting his health. Neither diabetes nor declining cognition is anything to ignore or speculate about.
Best of luck to you and your husband.
Contact your local Area Agency on Aging for resources you might be interested in, maybe even consider grief counseling (I would be grieved, too, if my spouse was having such decline).
If you have trouble leaving your husband alone at home then consider hiring a companion aid for him on a regular schedule so you can go out and live a normal life and make friends, join groups, go to events.
My neighborhood has a quarterly Ladies Wine and Cheese. The organizers send out a lot of invites and it's fun way to get to know your neighbors better. I worked full time and my kids didn't go to the same school as most the others, so it really helped me to meet the women on my block in such a way. It is fun. Sometimes you have to be the one creating the event (like a card game group, book club, etc). Bring people to you, rather than you going out to search.
Should you tell your in-laws? Yes, I would tell your BIL so that he has a chance to come see him while he still can. He may not, but you'd have done the right thing for your husband and can have peace about it.