We have a "One Touch" personal alarm for MIL with dementia and 89 year old dad who falls. You can set a radius around the home to be alerted when they cross that. MIL radius is very small so we get alerted almost as soon as she is out of the house. Dads radius is very large as he is well known within his village and locals keep an eye out for him, we only need it for him to register a fall and for him to press the button to talk to either myself or brother if he needs help ( MIL is incapable of using this function). The app will give us a location on request and you can check back on previous locations so you can see what direction they are going in. We get these for a small add on fee to the monthly charges for their care phones from the local council. It may be useful to get a care phone as there are all sorts of technology that can be supplied with them as dementia deteriorates. I found out what technology is available on the local councils website beforehand. When MIL was a lot better with her dementia we had an alarm and recorded message on the care phone to remind her to take her medication, now she is worse we have a door alarm to notify us if she goes out during the night. The carephone system locally is really flexible and hopefully it will be in your dads area too.