Where is the best place for my wife, with early onset Alzheimer's, to go in the event of my death?

I would never appoint a child unless there is only one. As you look through this site it is laden with horror stories about how siblings treat each other. There are also some where the children are able to work together, but they are the exception. You may want to consider a geriatric case manager to take over should something happen to you.

James,
This disease is so cruel, especially early onset! I am so sorry it has happened to your wife. Do you have her powers of attorney? Is there a second in line should something happen to you? There is no need to rush into this, but planning is very wise. Your wife may be able to live at home if there are resources and help and as her needs increase it will become a 24/7 job for someone if she stays at home which would be quite expensive. It may become necessary to place her in a facility even if nothing happens to you. As the disease progresses some of her behaviors may become very difficult for you to manage alone. You should see an elder law attorney to assist with the planning. And there is Medicaid planning that should be done to insure that you will have the resources that you will need while providing for her.

Much depends on her condition at the time. She might qualify for Assisted Living if her behavior is good. What you need to do is set up your Will so that the estate goes into a trust for her benefit. She will also need a Guardian, usually a younger person. My father had me appointed as my sister's guardian when was 80, with my other sisters as stand-by guardians. If you have children up to the task, appoint one of them.