Why Do Some People Forget Allah Is Watching?

My daughter is beloved by everyone and deeply committed to her faith. She regularly attends the masjid and assists children with memorizing Quran, known for her strong haya and modesty. She became engaged to her second cousin, who insisted she should trust him and agree to marry, promising a proper wedding ceremony later because his father was ill and undergoing surgery. Using religious guidance as pressure, he proceeded, and they entered into a full marriage contract. He claimed they were going to the court for the official marriage but instead took her to his family’s home. Nobody knew they were fully married yet, and his threats to keep it secret hinted he planned to leave. He later engaged with multiple women, shouted, drove recklessly when she was with him, and if she confronted him about his infidelity, he would prevent her from leaving and blame her for damaging his reputation. Eventually, he stopped answering calls. I spoke to him about their situation, but he didn't respond until, of course, she had to initiate divorce due to his absence. During her iddah period, she attempted reconciliation, but his reply was, "It's not my concern; I want to live my life." My question now is, how can parents speak falsely about a girl after all the wrong their son has done? I struggle to understand how anyone fails to remember that Allah observes everything. What should I do if they continue gossiping about my daughter? They're questioning why she consented to him. They're even commenting on her faith and character! Should I gather the community and clarify the truth to end this?