Ah Debbie. Someone etched in the long term memory of his even though his short term memory is lost.
How depressing such a life would be. All your memories of people younger than they are, or people no longer alive. Anytime someone actualy does convince you that is the case, it would only sadden you to come to the realization. The realization that everything that seems current and things you look forward to are from decades before.
A realization you would soon forget, and then be reminded again and again of when you wanted to do something with or visit someone from a different time.
He obviously is just trying to keep his romance with Debbie alive. You won't let him see or even speak to Debbie. Surely last he can remember things with Debbie were going well, yet you are keeping them apart.
That does seem kinda rude. Causing all kinds of hassle for a man just trying to see his loving Debbie.
That understandably has him upset.
It seems only yesterday that Debbie was thanking him for the flowers, yet you act like she is not there.
I wonder if Debbie is an old girlfriend or perhaps a wife that passed away before him?
In any case he probably does not have many prospects at this point in his life, so it is probably best he keeps the flame between him and Debbie alive.
I guess it is possible he could one day be violent if you keep him from seeing Debbie. After all he really cares for Debbie, and Debbie cares for him, she was just telling him so yesterday. Yet you won't even let them see or speak to eachother.
In all honesty though most days are probably similar to the previous ones. Like the movie Groundhog Day (
http://www.imdb.com/title/tt0107048/), except it is only a repeat for him. In his case he won't eventualy end up with the girl, Debbie.
However since he will be similar most days, he probably will not be much more violent than he has already demonstrated if alzheimer's related dementia is the problem.
So rather than an escalation with him more upset every time, it will probably happen relatively the same each time. Meaning if he has not actualy shown a tendancy to act violently when treated a certain way, he probably will not in the future treated a similar way.
Perhaps figuring out which way achieves the best results for future use would be best. Some tactics may illicit threats and hostility, and others have him calmly leaving. Find the winner, and repeat.