My cousin sister and her family are facing problems from her husband. My cousin does not want to go

My cousin sister and her family are facing problems from her husband. My cousin does not want to go for divorce and her parents are tolerating all the harassment due to fear. Her husband is threatening to take away their only child who is 3 years old if they did not comply with his wishes. My cousin is working, uncle (recently had a stroke and still unfit for bypass surgery) a retired pensioner, cousin's husband is not working (never worked; has always been dependent on my cousin's family since marriage). Can I file a police complaint against him so that he will stop harassing them? This is just to ensure the safety of my cousin, her kid and her parents and to prevent him from ever thinking of causing any harm to them in the future? This is only to give him a warning, not to get him arrested as none of my cousin's family will agree to his arrest. My cousin is unwilling to separate from him or file a case against him. In case any harm occurs due to him to my cousin or her kid or her old parents, I don't want him to go unpunished.