Siblings can also have a hand at talking sense to their sisters, parents understand one part of their child but only a sibling can understand the other. Voice your opinion if you're worried for her. But remember what consequences it could bring and if you're willing to take the risk.
>>2 It's true that it's your sister's choice. But us guys on the threads don't know the full scenario, who knows maybe the guy changed from his 15 year old self. I still don't have much to say, just some advice though.