Alcoholic

If her drinking doesn't bother your son then I wouldn't intrude.

It isn't unusual for people to drink more when they are on holiday.

Don't say anything to your son.

My son has confided in me that his new girlfriend drinks too much and he doesn't feel good about it- he says she is trying to cut down though. I'm leaving it to them to sort out and I think so should you.

I think it depends on how close you are to your son, meaning do you usually have personal conversations. If you are, then you may discretely say something to him, and ask whether he is concerned.

I've always thought drinking was a problem when it affects your relationships, your budget, your health or your work. Some people can drink quite a bit without causing any issues, but for many it does cause problems.

I would say nothing to your son that is between themselves and your thoughts may not be well received.
It is a misconception that all heavy drinkers are alcoholics

Whether she is an "alcoholic" or not is irrelevant. Two thirds of a bottle of vodka plus other drinks is a lot for anyone especially a young woman.
But you can do nothing about it and discussing it with your son will not end well.
Try really hard to ignore it and just make their time spent with you as happy for all as possible.
The only time I would get involved at all would be if she intended to drive while drunk and then I wouldn't care who I upset. That would be my line crossed. The outcome of that could be far far worse than upsetting someone.

Only intervene if she is potentially endangering the lives of those she is responsible for…….ie driving under the influence, otherwise non of your business.

I agree that you should be very cautious about intervening. However, if it does get to the point where either or both of them admit there is a problem, I strongly recommend that your son goes to Al Anon. This is for people with an alcoholic in their life and it was a real life-saver for my adult child whose partner is an alcoholic.

Your only concern - and that must be approached very carefully - is if your son and girlfriend's drinking is placing your grandchildren at risk.

If your DIL drinks this amount on a regular basis, which is way over the recommended units for women, then her body will react in the near future. She sounds like a functioning drunk. Someone who is pretty much under the influence most of the time and tops up frequently. Those drinkers can consume huge amounts of alcohol but appear a bit tipsy to onlookers.
Say nothing at the moment but keep an eye on things.
My concern would be that she isn't driving. Alcohol stays in the body for a lot longer than drinkers realise with catastrophic consequences. Having a booze filled evening and taking children to school would not be a good idea at all.

I feel the same as Sarnia. I’d say keep quiet but be on alert also, my view is regular heavy drinkers probably are alcoholics and are addicted to it. They themselves will not see it until something occurs and won’t hear it from anyone trying to tell them otherwise. You will just have to be ready.

Dd was married to an alchoholic. Unless they admit it and want to get help there is nothing you can do. Dd did report him to the Police on one occasion after he drove off in the car. Eventually she got divorced as he was becoming violent when drunk. He is now with someone else and they spend all the time in the pub drinking happily together and she has several children. So I don’t think there’s a lot you can do. You could try having zero proof beer in and offer that and say you and your dh are trying to follow government guidelines for the sake of your health. They may take the hint ……….or not.