My father had alzhiemers and my Mother had a hard time keeping up with him, he would go outside and she wouldn't know it. So my uncle had her a talking alarm system put in. It cost under a $100. If he open the back door a voice would tell her the back door had been open, if he opened the front door she would  here someone has open the front door. It had 8 zones so she was able to know when he was upstairs, she also knew if he went passed a certain point in the yard, if he was outside alone. She also had a childs alert that she kept on him, if they went to the store if he got out of sight she just pulled out the locator and found him. It helped her and at night she slept better knowing he could not leave the house or go into the kitchen without her knowing.

my thoughts are with you. My dad also suffers from alzheimers however is more advanced and now  he is in a home. He started to refuse to allow his wife to come into the house and also started to due some very dangerous and unprepictabe behaviors. Unfortunately this disease is very tough on family membrers as he is now to a point where there is no recognition and very little communication. I wish you the best with your dad and hope his progression is slow,. Diane