My daddy (who has Alzheimer's) frets if I don't call every night at 8 pm. Usually I can do this. But on occasions (like when I'm out at a movie, watching a play or even cooking a late dinner) I can't. I tell him (he can't remember) and my aunt (his care provider) that I'll be gone that night, but... If 8 o'clock comes and I'm not calling he gets upset. Any suggestions.
I like FF's idea, worth a try? Or - I'm afraid this falls on you :/ - how about setting a reminder on your cellphone and putting in the quickest possible call before you go in for Act 2, or while you're waiting for popcorn, or once the potatoes have come to the boil..?
How old is your father, if you don't mind my asking?