We understand your concern and fear regarding the situation you're facing. Firstly, it's important to remember that our battle is not against flesh and blood, but against the rulers, against the authorities, against the world rulers of this darkness, against the spiritual forces of evil in the heavenly places. Ephesians 6:12 WEB.
We must stand strong against such spiritual warfare, For though we walk in the flesh, we don't wage war according to the flesh; for the weapons of our warfare are not of the flesh, but mighty before God to the throwing down of strongholds. 2 Corinthians 10:3-4 WEB.
It's clear that you are feeling harassed and unsafe, but let's remember that God has not given us a spirit of fear, but of power, love, and self-control. 2 Timothy1:7 WEB.
It is only in the name of Jesus that we can find true protection. The name of the Lord is a strong tower. The righteous run to it, and are safe. Proverbs 18:10 WEB. Also Jesus said, 'Until now, you have asked nothing in my name. Ask, and you will receive, that your joy may be full.' John 16:24 WEB
When we are under attack we are to appeal to God in prayer.
Is anyone among you suffering? Let him pray. Is anyone cheerful? Let him sing praises. Is anyone among you sick? Let him call for the elders of the assembly, and let them pray over him, anointing him with oil in the name of the Lord, and the prayer of faith will heal him who is sick, and the Lord will raise him up. If he has committed sins, he will be forgiven. Confess your offenses to one another, and pray for one another, that you may be healed. The insistent prayer of a righteous person is powerfully effective. James 5:13-16 WEB
Let's pray together for your situation:
Dear Heavenly Father,
We come before You in the mighty name of Jesus, seeking Your divine protection and intervention. We pray for this family being harassed by this vindictive individual. We bind the spirit of harassment and hate, and we loose the spirit of peace and safety upon them. Make it so that this vindictive satanic person and his plans will have no power or ability to take root or effect any harm or harassment in Jesus' name. We ask for this family to be able to rest in peace and comfort.
We pray for wisdom and guidance for this family, that You would direct their paths and keep them safe from all harm and danger.
We also pray for the person who is causing this harassment, that Your love would touch his heart and bring conviction and repentance. And if he be unwilling to repent and turn from his behavior, we pray that You, Lord, would thwart his plans and bring his evil deeds to an end.
Help this family to remain strong in their faith, trusting in Your promise to never leave them nor forsake them. Let this testimony be a tool to bring You glory.
We ask this in the name of our Lord and Savior, Jesus Christ. Amen.