Two or even three glasses of wine had over a meal shouldn’t have a negative effect, unless the man was very thin, as the effects of alcohol depend somewhat on body weight. On the other hand, three glasses of wine, followed by a beer or two imbibed later in the evening, nearer bedtime, could definitely have an effect. In other words, if a man is drunk, he might not be able to maintain an erection, but if he’d had some wine earlier, especially with a meal, it shouldn’t have much of an effect on his erections.

You should be aware that any problems with erectile function could be a first sign of circulatory or heart problems. So if the drinking is really in moderation and with dinner, then I would urge you to tell this man to go see a doctor and inform him of the problems he’s having. It could save his life.