Girl X has been "alone" for some time, whatever alone means. Desires relationship/companionship, etc. I.. don't have any time to entertain these things, so I'm supposing she moved on, yet desperation kicks in, and a 'companion' is found. Companion X smokes, drinks, works a menial job in a restaurant, significant covering of body with tattoos, and is NOT a student. Girl X looks beyond this (or doesn't see this at all). It is clear that X brings demise, and eventual pain.
Interference or Intervention? Unfortunately, very little can be done; few proactive mandates on this issue will pass. It's well beyond interference, and well out of acceptable behavioral standards for intervention. Girl X is not close enough for intervention, so both interference and intervention are ruled out, and the only option left is to watch and learn. (and this should be amusing)
Perhaps I'm expected to say things, but I don't. I don't like to interfere, unless I accidentally blurt something out, or it's necessary. If you ask me what I think of something, you'll almost never get the whole opinion. That's just how it is. You should be prepared for the entire opinion, and I'll give it if you ask, but don't offer any rebuttals.
I tend to have stricter rules for intervention. Likewise, I would prefer people not openly passing judgment on my actions, as I don't of theirs'.