Intro

A friend of mine who i love dearly has been dating this chico for a while. And as a friend who hates to see her cry or be taken advantage of, it seems this relationship she has is...somewhat unhealthy.

She's a young one who has barely dated (she's filipino, they have that strict dating thing from the family) anyone. She's new to the whole situation of having a long term relationship.
They've been dating for many months now and as a friend, I begin to notice things. He drags her around, he's seems strict about her activities and such. It seems as if he's controlling her and she doesn't know it.
Now PDA if it's hugging n such, i have no problem, but I'm on stage working on someting and their making out 2 feet in front of me/everyone else, I gotta draw the line.
Thing is, I can't just say, "Hey sweety, you can go into a closet and do that crap, otherwise take it somewhere else."
And I know her chico pretty well. He's a very dark/emotional character. When he's sad, she's sad, when he's happy, she's happy. Hey it's nice to have that spiritual/emotional connection, but like i said, you gotta draw the line somewhere. Plus he's got so many bones in his closet, if you opened it you'd find all hell in there. No joke. And of course she doesn't know about them. And unfortunately I do. I know if I tell her, all hell will break lose between them and between me and her.
Her mind is slipping, she thinks she needs to spend time with him 24/7. Basicaly forgetting all her friends that give a crap or anything she commits to. And to chico "friends" to him is non-exsistent. Meanging very few and very little contact.

So I know what not to do. But then the question is, what should I do?
I know talking to her is a must, but what does one say something to someone so delicate. And knowing her, I don't know how the hell she'll respond, I'm trying my gosh dern hardest not to cuss, not to go all 'hurtfully truthful' on her. But DAmn! I really want to at this point.

He's her dark prince, and she's his little bit of sunshine. I don't wanna destroy that. But it's bothering me all at once. She's gotta learn, you gotta set boundaries, you gotta wear the pants sometimes.
Any suggestions?

(Just for the record, no I'm not interested in dating her; and her chico does know he's a big deal for her. They're both 'fresh out of highschool' age. She's about to go to college come September and she knows if she dumps him he'll go all 'suicidal' and such. What a joy this guy is.)