My 85 year old husband has recently been diagnosed with dementia. I am completely at a loss regarding how to care for him.

First I would talk to his doctor about putting him on medication for his sun downing as there are several out there.
Then it's important that you educate yourself about the disease of dementia, so you can be better prepared for what's ahead.
You can either "Google" to find out what kind of help is available in your area(Area Agency of Aging, Senior Services, VA etc.)or as already suggested you can click on the link at the top of this screen that says "find care."
Then I would suggest that you find a local caregiver support group as that will be very helpful for you to be able to share with others who understand exactly what you're feeling and going through.
I'm sorry that you're now on this journey with your husband. It will be hard, no ifs ands or buts, BUT you can do it, because you're stronger than you know.
And if his care gets to be just to much for you, you will have to place him in a memory care facility. And if money is an issue then you'll have to apply for Medicaid.
I wish you the very best as you walk this road with the man you love.
God bless you both.

First of all, do you have a will? A power of attorney? A health care proxy? It if of major importance and worth the money to see an eldercare lawyer right away even if you already have the above documents. A lawyer with expertise in Medicaid will be able to show you how to spend down assets to qualify for Medicaid or how to use a non-revocable trust to shield some assets. In home care is extremely expensive and that is why you need an experienced lawyer so you can eventually get Medicaid. Also, I am assuming you have a good neurologist who diagnosed him. If not, get one. You may also consider a clinical trial because they pay very close attention to patients and their caregivers and he may be in an early stage eligible for the newer medications. Also, even if does not have Alzheimer’s or another type of dementia, contact you local chapter of the Alzheimer’s society because they can give you lots of good advice including support groups. Your post indicates you are probably very anxious and getting support can be very helpful for you. Perhaps your husband’s “sun downing” isn’t sundowning but perhaps he is equally anxious because of his diagnosis. Best of luck

You can access in home caregivers through this site, on the right hand side of your screen, or through an agency search online, Care.com, etc. Dementia is something you'll need to learn about if you plan to care for your husband at home. Medicaid may be available to pay for long term care in Skilled Nursing if finances are limited, and if his care becomes too much for you to manage.

I suggest you read this 33 page booklet online about managing dementia and what to expect with an elder who's been diagnosed with it. Showers are discussed in the booklet as well as lots of Do's and Dont' s for dealing with dementia sufferers.

Understanding the Dementia Experience, by Jennifer Ghent-Fuller 

https://www.smashwords.com/books/view/210580

Jennifer is a nurse who worked for many years as an educator and counsellor for people with dementia and their families, as well as others in caring roles. She addresses the emotional and grief issues in the contexts in which they arise for families living with dementia. The reviews for her books are phenomenal b/c they are written in plain English & very easy to read/understand. Her writings have been VERY helpful for me.

The full copy of her book is available here:

https://www.amazon.com/Thoughtful-Dementia-Care-Understanding-Experience/dp/B09WN439CC/ref=sr_1_2?crid=2E7WWE9X5UFXR&keywords=jennifer+ghent+fuller+books&qid=1657468364&sprefix=jennifer+ghent%2Caps%2C631&sr=8-2

The 36 Hour Day is another excellent reference type book you should pick up. Amazon has both books.

Alz.org is a great website to access and has an 800 phone number for questions. The line is manned by live people.

In person support groups as well as online support groups are very helpful too,

Teepa Snow is a dementia expert with lots of YouTube videos that are used as training guides for dementia caregivers. Check them out.

Also, take time out to care for yourself and get respite while taking on this huge task. Your life is important too, not just DHs. TWO people's lives get slaughtered when dementia enters the picture, not to mention the rest of the family members 😑

Best of luck to you