We understand the grave nature of your situation and we stand with you in prayer and support. Firstly, we must acknowledge that the behavior of your in-laws is not only toxic but also sinful, and it is important to address it as such. The Bible tells us to put away all bitterness, wrath, anger, clamor, and evil speaking (Ephesians 4:31 WEB). Their actions are not in line with God's will and they need to be held accountable and to know the forgiveness of Jesus Christ.
We also need to address your husband's response. The Bible calls men to love their wives as Christ loved the church and gave himself up for her (Ephesians 5:25 WEB). This means protecting and caring for you and your son. It is not godly or acceptable for him to ask you to ignore this behavior. You are not called to endure this suffering, but to confront it with love, truth, and grace.
We must also remember that God hates divorce (Malachi 2:16 WEB) and we should pursue reconciliation and forgiveness whenever possible. However, this does not mean you should stay in a situation where you and your son are not safe.
Let us pray:
Heavenly Father, we come before you in the name of Jesus, lifting up our sister and her family. Lord, you see the injustice and suffering they are facing at the hands of their own kin. We pray for your divine intervention, God. Protect them from the violent behavior of their in-laws and give them wisdom to navigate this situation. Lord Jesus, you are the Prince of Peace; grant them your peace that surpasses all understanding (Philippians 4:7 WEB). Strengthen our sister and her son, give them endurance and courage to face each day. Soften the hearts of their in-laws and convict them of their sins. Bring them to repentance and reconciliation. Lord, we also pray for our sister's husband. Open his eyes to the gravity of the situation and give him the courage to stand up for his family. Guide them all in your truth and love.
Sister, we encourage you to seek godly counsel and support in your local church or with Christian friends. It is important to have a community of believers around you who can help and support you in this time. Remember, Jesus promised to be with us always, even until the end of the age (Matthew 28:20 WEB). He is with you and will never leave you nor forsake you (Hebrews 13:5 WEB).
Lastly, we noticed that Jesus was not mentioned in your request. It is only by the name of Jesus that praying to God is possible. (John 14:6-7) It is in that name that God saves us. (Acts 4:12) May you be assured of Jesus as the only way to God.
Stand firm in your faith and keep praying, trusting that God is working even in this difficult situation.