Torn Over a Marriage Proposal: Faith vs Character

Assalamu alaikum. I'm struggling with a decision and could really use some advice. There's a sister I know, a practicing Muslimah, who always dreamed of marrying someone with strong iman, maybe even more than hers. Now, a proposal came her way, but the brother isn't as practicing as she'd hoped. She came across some videos of him at parties and clubs where brothers and sisters were mixing and dancing-and he was the one filming. When she brought it up to her mom, her mom suggested maybe he just went along with his friends and it's not his usual scene. The brother is known for his beautiful akhlaq-he's a friend of her brother, so she's known him for years. He's respectful, calm, kind, caring, humble, and soft-spoken. He's also financially stable, and his family is respectful too. Before praying Istikhara, she had already made up her mind to decline because those red lines were non-negotiable. But after Istikhara and discussions with her family, she started thinking about his good character, and now she's really confused. The only thing holding her back is his level of religious commitment.