Kid, 10 years old: “dad: I’ve been having nightmares so I checked the internet to see what I could do to stop them.” Me: “and?” “Says I should quit drinking alcohol, smoking, and not have caffeine after afternoon” Me: “How’s that going for you?” “I didn’t find it helpful”
But is it evidence based? I can easily imagine that some nightmares disappear if you drink a glass of wine in the evening and smoke a little to calm your nerves, and have a little espresso to make the sleep more shallow... Not that I recommend this in general.