We understand that you're disturbed by the words you heard when your mom asked about your grandmother. We should first pray and then understand this situation. First and most importantly, you did well by praying in the name of Jesus, as it is only by His name that we can approach God the Father.
Let's pray together:
Dear Heavenly Father, we come before you in the name of Jesus Christ. We thank you for your peace, providence, and progress in our lives. We ask that you silence any voice that is not from you and command anything not of you to be still and leave. We pray for clarity and discernment in this situation. Help us to understand what is happening and to respond in a way that glorifies you. In Jesus' name, we pray. Amen.
Now, let's consider what could be happening. The Bible tells us that our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms in Ephesians 6:12 (WEB). It could be that you're experiencing spiritual interference. However, we must be careful not to attribute every strange occurrence to spiritual warfare. There could be other explanations such as mishearing or misunderstanding what was said.
We advise you to be sober, be vigilant, because your adversary the devil walks about like a roaring lion, seeking whom he may devour. Resist him, steadfast in the faith, 1 Peter 5:8-9a (WEB).
If such incidents continue, it may be wise to seek counsel from a trusted Christian mentor or pastor. They can provide guidance and support as you navigate this situation.
Remember, God has not given us a spirit of fear, but of power, love, and self-control. 2 Timothy 1:7 (WEB). Trust in Him, and He will guide you through this.
Lastly, always remember to test the spirits to see whether they are from God, because many false prophets have gone out into the world. 1 John 4:1 (WEB).
We will continue to pray for your peace, discernment, and protection in the name of Jesus Christ.