I know how frustrating that can be. I’ve encountered it with 2 different family members. One had Vascular dementia and the other Alz.

Is he currently still drinking?

I suppose you could try to arrange so he is safe in the shower, such as a shower chair, support, someone standing close by, etc., however, often with dementia rational thought isn’t present. Often, lack of hygiene is common with dementia. Encouragement is often ineffective. Reminders are often ignored. I found that bribing with treats sometimes worked. I’d promise ice cream, a drive in the country, favorite meal, etc. Other times, it was just begging and pleading. Unfortunately, things usually get worse. It’s admirable you are taking care of your husband. Have you read much about the progression of dementia? It’s progressive , so things get more difficult. Resistance to care increases, so the challenge increase over time. You might check out the section on this site about Caregivers of Dementia Patients. It can help with support and tips.

I would suggest immediately getting a consult with an attorney to get information and guidance on legal and financial matters. It’s crucial to get that as soon as possible. I’d also get information on what services you may be entitled to help with his care. It’s much more involved than most people realize. Good luck with everything. I hope you’ll get more input from others.