Very sorry to hear about your dad's unfortunate condition. Sounds much like dimensia. My wife's great grandmother had it. Some of the things they say and do will make you laugh beyond belief. If in fact that is the case, something to be concerned about is them getting lost and not knowing how to get home. Talk to some siblings (yours or his if still alive)or his friends that he may have shared this information with. It may be a good place to start. Best wishes.