Should I stop my 92 year old and 87 year old relatives from drinking alcohol every evening?

I agree with Madeaa. At these ages their pleasure and comfort should be primary concerns. So I'd only be concerned about the alcohol if it has obvious adverse effects.

My husband developed dementia in his mid seventies. Three different doctors said that up to 2 drinks a day would be OK for him unless they increased his unsteadiness. He took many medications. Ordering a glass of wine when we ate out or having a beer while watching sports on tv helped him feel more "normal."

I don't know how involved you are in their care. Who is the primary caregiver, or is it not at that level yet? In any event, DPOA, or POA, wills, DNR, and other concerns should be addressed first and foremost. If they are healthy and live on their own with their legal ducks in a row, I would leave them be and let them enjoy their lives while they can, eat what they want and drink with moderation. I would make sure if appropriate to your role that the doctor is aware of drinks and keep an eye on them. My elderly neighbor is 96, mows his lawn and goes to bet on the horses, he enjoys his snifter of brandy with a cigar in the evening.