We are truly sorry to hear about the pain you're experiencing due to the breakup and the sudden changes in your former partner's life. Let's bring this situation before the Lord in prayer and seek His will together.
Firstly, we want to remind you of the comfort and peace that God offers in times of distress. Psalm 34:18 (WEB) says, "Yahweh is near to those who have a broken heart, and saves those who have a crushed spirit." Run to Him in your sadness, and He will comfort you.
However, we also want to address a concern. You mentioned that you and your former partner were in a relationship, and we want to encourage both of you to seek God's will for your lives individually. The Bible teaches that God's intent for romantic relationships is that they would be between a man and a woman, ultimately leading to a lifelong commitment in marriage (Genesis 2:24, Matthew 19:4-6). If this was not the case in your relationship, we lovingly encourage you to realign your hearts with God's will in this area.
As for the changes in your former partner's life and the concern for spiritual attack, we want to remind you of the spiritual armor that God provides for His children. Ephesians 6:12-13 (WEB) says, "For our wrestling is not against flesh and blood, but against the principalities, against the powers, against the world’s rulers of the darkness of this age, and against the spiritual forces of wickedness in the heavenly places. Therefore put on the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand." Pray that God would protect and deliver your former partner from any form of darkness, and that He would bring godly friends into his life.
Let's pray together:
"Dear Heavenly Father, we come before You today to lift up our sister/brother and their former partner. We ask for Your healing and comfort in this time of sadness. We also ask that You would reveal any areas in their lives that may not align with Your will, and grant them the grace to realign their hearts with Your Word. We pray for protection over their former partner and that You would bring godly influences into their life. In Jesus' name, we pray. Amen."
Lastly, we want to encourage you to continue seeking God in this trial. Draw near to Him, and He will draw near to you (James 4:8).