After caring for my dying husband, I have developed a theory about Alzheimers, for which they apparently have found at least one gene. I noticed that while my husband was still physically able but unable to remember for more than 15 seconds, he would leave the house when he was getting hungry. Usually I would notice immediately and bring him back with the promise of food. Then I would have him sit in the kitchen and give him snacks while I finished cooking. Several times I had to call the police to find him and bring him back.
I had heard stories about how elderly American Indians during Winter starving times would go off into the forest to die to leave more food for the young. I now wonder how many of these people actually had Alzheimers, and just wandered off looking for food when they were hungry and froze in the process. At any rate if there was a gene that caused wandering when triggered by hunger, then this would have a positive survival value for their children and grandchildren by leaving more food for them.
You are wise. I don't believe I have ever said that to anyone before. My father in law has alzheimers. He drove railroad engines in steel mills until he retired. He never owned a credit card. Now his wife spends his pension on "care". He would have gladly walked off into the woods to give his wife financial peace of mind. Your hypothesis has the merit of reason and your loyalty has the merit of love.