While on another forum for caregivers of autistic children, this device was recommended by one of the parents. She is able to keep track of her daughter who is an "eloper" and can see where she is - on the school bus, at school, etc. She commented that she can also communicate with her daughter and "drop-in" to hear what is happening when she's at activities. Seems like it would be similarly useful for dementia and memory impaired adults.
https://www.angelsense.com/
Some people use air tags too. I suppose there are different kinds of tech products for this purpose.