Struggling with my 15-year-old sister’s big change - need advice, please

As-salamu alaykum, I’m 26F and my sister is 15 (I also have brothers 24 and 21). Our family is having a really hard time and I’d appreciate some outside perspective. A bit of background: we’re a Muslim family. We lived in London until 2013, then moved to a mostly white area. My brothers and I managed to adapt while holding on to our values, and though it wasn’t always easy it was okay. Over the last year my youngest sister has changed a lot and it’s taking a toll on everyone, especially my parents. She’s become very withdrawn at home, stays in her room most of the time, barely speaks unless she needs something, and often talks very disrespectfully to our parents. She’s told them she hates us and says we don’t care about her - which hurts because our parents have sacrificed so much and truly love her. She’s very close to two friends she made last year. With them she’s happy, bubbly and outgoing; at home she’s cold and distant. Around the same time she stopped wearing her hijab and began dressing and presenting differently (fake nails, lashes, etc., even at school). Her friends have boyfriends and vape, which conflicts with how we were raised. From our side it feels like she’s drifting away from her faith and from family and it’s devastating to watch. My parents are emotionally worn out - I’ve never seen them like this - and I feel helpless as an older sister. One of the hardest parts is that my parents don’t feel able to discipline her in the usual ways (taking her phone, grounding, restricting contact with friends). When they try she reacts very badly - extreme anger and emotion - and she’s said things before that made us worry about pushing too hard. So my parents feel stuck between wanting to set boundaries and fearing they’ll make things worse. We’re also thinking about moving back to London to be nearer extended family and a stronger Muslim community, hoping that being around people who share our beliefs might help guide her back. But we’re worried that could backfire or push her further away. I’m not trying to criticise my sister - I love her and want the best for her. I know she’s young and figuring things out. I just don’t know how to support her without losing her completely. If anyone has experienced something similar - as a sibling, parent, or as the teen herself - please share what helped and what made things worse. How do we rebuild trust and connection before it’s too late? JazakAllah khair for any advice.