Where do we turn for help for the widow of a veteran who has been diagnosed with dementia and Alzheimer's?

Call the Area Agency on Aging and the VA.

The VA has a benefit called "Aid in Attendance" -it pays for caregiving. Certain rules apply, but it is available to Veterans and their spouses. You can Google the term to get an idea of the rules and who qualifies, etc. and also speak to the VA about applying for this benefit. Best wishes.