FWIW
Diet Sunkist does contain caffeine. Whether he “believes it” or not. He might think it doesn’t but the facts is there’s 42 mg. per 12 oz. Can (or 3.5 mgs. per oz. if he’s drinking it by the liter.
You should tell him that he can think whatever he likes because people are entitled to their own opinions; but they’re not entitled to their own facts :D
I would second the suggestion of Benadryl. It comes in 25 mg. tablet so I wpuid suggest at least 2 tabs.(50 mg.) to start off with.
I’ve been taking it for years with no ill effects or addiction. I usually take 3 tablets but I’m taking it for my allergy and sinus problems moreso than sleep. If for some reason I don’t have any I can still fall asleep so it’s not addictive that way. But I do wake up with one hell of a lot of nasal congestion.
One little aspect to take note of. Yes, there is kind of a drowsy effect within about an hour more after taking it (which is why I don’t use it in daytime) but it’s also easy to resist that and keep on reading or watching TV or whatever.
So, if one is resisting that slight drowsiness, it will wear off after a half hour or soand then you’re right back from where you started.
He should take it when he knows that he’s seriously ready to go to sleep and stop doing anything else and don’t resist it.