I noticed my cousin seems distant from our faith and I really want to help her find her way back to Allah

Hey everyone, hope you're all well inshaAllah. English isn't my first language so sorry if I make mistakes. Me and my cousin are both 17 this year, and we've always been super close. But since after the pandemic, I've noticed she doesn't wear hijab anymore. Whenever I bring it up, she says it shouldn't matter since we're family, but it honestly makes me feel uneasy. Yesterday, I went to her place for Eid. She wasn't dressed modestly, but I didn't say anything. We were just chatting casually and I asked for her TikTok username. She doesn't post much herself, but when I checked what she shares-astaghfirullah-it's all about leaving Islam and atheist stuff. I'm really worried about her and I just want to support her in returning to Allah. Does anyone have advice on how to gently approach this? JazakAllah khair.