How do you prove someone is a boarder-line Alcoholic?

My Bestie never dealt with any type of alcohol abuse in her life. The rest of girl group has, problem is with that...One is in France and the other is in Virgina. The three of us had dealt with it on various levels, Franchie's levels are talked about much simply because she was bit to young but I think it had to do with the current situation in her country at the time. Virgina had the abusive drunk issue. I had the driver issue.

Bestie's Boyfriend is borderline not all there yet. I see the headlines in bright flashing lights. She doesn't.

When the group is out, he only buys himself and Bestie drinks.
He rather go to one bar (big indication)
If they are at his place he'll add more to her drink when she is watching. (Scary!)
Never goes out anywhere, where he can't get a drink later.
He goes to bar regardless of how tired he is.

There is no way to tell her. I tried. Of course she denies me experience and tells I don't know what I'm talking about.

Well it's hard to judge when I haven't seen it myself. I suppose the best way is to talk to other people who know the two of them well enough. Ask them what they think. If you're the only person out all your mutual friends then it's possible you're seeing something that isn't there. However if other people are seeing this as well then maybe you can talk to them about it as a group. One opinion against another doesn't always hold much ground but if several people are seeing something that she isn't, she might rethink things.

my boy sees it. He's a friend of Bestie's Boyfriend.

Keep asking other people. If at least five or six in total agree with you, then perhaps you could approach about it together?

There isn't any hard line that shows someone is an alcoholic versus if they are not. It's usually something you judge on a case by case basis and isn't that easy to figure out. So you can't prove it to them without a shadow of a doubt because it's kind of a gray thing (rather than a black and white thing.)

Although I do agree with silenttiger.

Just know, most people who have addictions (drug addicts, food addicts, sex addicts, alcoholics) know that they are deep in their heart. Their life usually tends to fall apart from their problems, so even if you don't "convince" them of it, I think they already know. They're just in denial about it because they probably don't think they have the strength to conquer it and also they love it too much to even try.

Hmm... well as someone who use to basically breathe the bottle, I can see how the things you've mentioned could freak you out.

Have to agree with silenttiger43 & The Enchanted Tiara, If a lot of other people see it too, this could be a very big problem and should be approached with more than just one opinion.

Also, he could be secretly harboring a troubling issue that he hasn't fully dealt with yet. I know that when I first picked up a drink to feel good, my best friend and the biggest influence of my life had died and I couldn't have cared less about anything else.

Maybe you should have her talk to him about his drinking, or since she doesn't see this drinking as a problem, have her sit down with him and ask him about what's happened in his life, and then ask her about it.
There are a lot of things that lead a person to drink excessively, and sometimes, they just need to talk it out to realize what they're doing.

Hmm... well as someone who use to basically breathe the bottle, I can see how the things you've mentioned could freak you out.

Have to agree with silenttiger43 & The Enchanted Tiara, If a lot of other people see it too, this could be a very big problem and should be approached with more than just one opinion.

Also, he could be secretly harboring a troubling issue that he hasn't fully dealt with yet. I know that when I first picked up a drink to feel good, my best friend and the biggest influence of my life had died and I couldn't have cared less about anything else.

Maybe you should have her talk to him about his drinking, or since she doesn't see this drinking as a problem, have her sit down with him and ask him about what's happened in his life, and then ask her about it.
There are a lot of things that lead a person to drink excessively, and sometimes, they just need to talk it out to realize what they're doing.

i agree with betterevil1