Originally Posted by
onipar 
So when it comes to when and how much she drinks, is it really best I say nothing?
Certainly say nothing while she is drinking, that is completely counterproductive.
When she is sober, I think it is totally fair to express your concern that she drinking to the point of making you uneasy or concerned for her health. But keep it in the realm of how it makes YOU feel, not what you think she should or should not be doing.