Sister doesn’t like my boyfriend

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Sorry if this is long but i just need some advice 😩 about 2 weeks ago my little sister moved in with my boyfriend and i , a few days after that she started acting weird and ignoring him , he sensed it also and things have been awkward asf because now he doesn’t care to be nice anymore and plus she brought her two dogs here that he now wants gone ( we aren’t supposed to have dogs on the lease ) . Well today It turns out she saw his old tinder profile from 2 years ago and thought he was still on it , he deleted the app not the account. I knew this immediately and told her that’s what happened .she’s still acting like she will have a attitude with him when he gets home from work . He deleted the account now but mind you he’s sent her money and she smokes free weed that he buys ! Plus it’s a giant risk having these dogs here .So how do I get her to stop acting like this ?