Anonymous wrote:i feel for you. I understand what it's like to dislike the significant other of your sibling. With that being said, you can't say anything unless he asks for your opinion. And in that case, you have to tread lightly.
Let your brother make his own mistakes.
+1
And think back to when you were 27. Maybe part of her personality is really bravado in front of boyfriend's family/all older people. Give her an honest chance, and maybe she will relax and mature. In the meantime, be happy about your brother's spark.