OK so my brother is dating this girl. And at first I really liked her we got along well and seemed like we could get close. But now I have a gut feeling that he really needs to break up with her. She whines about everything! She can't even have a normal conversation without whining. She always has to be touching him even when he doesn't want to be touched. He's the type guy that doesn't like to be affectionate in front of people and she's the type of girl that likes to be the most affectionate around people. They have only been together for a couple months and because of her jealousy he has already threatened to break up with her. My best friend my brother and me were really close and now because she gets jealous he can't hang out with us because if I even just have to pee that would leave him and her alone together. I am hesitant to say anything because the last girl he dated seriously I had to bring to light the things she was doing. So should I stay out of it this time and let the relationship break apart itself or should I tell him what's going on?

In two words: Butt out.

Be a good sister and be silent. Be polite to the girlfriend. If you love your brother, you will be silent.

Hi Green,

I know that being a sister you look out for your brother and want what's best for him, which is great, but I think it's best sometimes to let him figure out things with his girlfriend himself. He may really love her, but if not, he will need to be the one to find out. If things however don't work out for him, as always, be there for him.

You can engage him in "what if" conversations about nothing in general. Without discussing her directly, bring up her character traits and habits in the form of a "do you like this" kind of query.

"Johnny, which would you say you prefer - a girl who is pretty independent and is capable and confident on her own, or a dependent girl who relies on you for everything?"

"Johhnny, do find jealousy to be a compliment to you, or a detriment to your relationships?"

"Johnny, when it comes to affection, are you a "public displays of affection" or "private time only" kind of guy?"

"Johnny, what's more attractive to you...a cup half-empty or a cup half-full person? Someone who finds fault with every situation or someone who finds good in every situation?"

See, you get to talk about her without ever bringing up her name. When he answers the right way, ways that indicate his current g/f is wrong for him, he'll know what you're doing, but he'll let you do it as long as you keep her name out of it.

If you REALLY want to have fun, have that same conversation in front of her. No Names! Hehe.

It sounds like your dating her not him, butt out!

As JB said you can discuss general things of what do you want in a relationship, what are real turn offs to you, and so forth but it is best to keep your opinions of their relationship to yourself.
I have known many married couples that have separated and turned to a mother or best friend for advise. They would say things like my no good husband was cheating on me and blah, blah, blah... The mother or best friend would try encouraging them and be moral support with yeah you are better off without him. Cheating is never good. I didn't trust him ever since the time he... blah,blah, blah...
Then they work things out get back together and who is the one that is snubbed by the two of them!?