I would like opinions on if this dream was just a coincidence or if there could be more to it?
It's possible, especially if you and your sister were close. Many people feel things or dream things concerning their relatives or even friends before they happen. I'm glad your sister is all right.
The Bible says God speaks to people through dreams, and over time I have learned more about it. There are many testimonies from Christians who had dreams where something strange was happening to a loved one. This is God speaking to their spirits to alert them their loved one is in danger, and that they need to pray for them. I recall this case where a man was called to pray and pray, and later he learned his brother was in a big car accident. Law enforcement had no explanation how he survived and with such few injuries. I have had such experiences myself. In one case I was on vacations in another state when I felt the Lord wanted me to pray and pray. Later than night I was watching the news and learned that a tornado came through my neighborhood. The houses of my neighbors were damaged, my house had no damage at all. This is one of the beautiful things when you have a relationship with God through christ and you learn to listen the prompts of the Holy Spirit. It is a relationship he wants, not religion. it sounds to me that God also speaks to you, but you are not aware that it is HIM...as it happened with your sister. I hope you will receive him as your savior and pray for wisdom to discern his voice. it cam make a huge difference in your life, and in the lives of your loved ones. How to accept Jesus Christ as your personal Savior and Lord? It is the easiest thing in the world. Just close your eyes, focus on him and pray something like this: "Lord Jesus, I repent of all my sins and I ask you to wash me clean. I am sorry for all the bad things I have done and the many times I broke God's Will. Please forgive me and fill me with the gift of the Holy Spirit. I want to belong to God. I want to be adopted into his family as his child. Come into my heart. I give you control over my life. Please lead me through the Holy Spirit and make your Word real to me. Fill my soul with the peace that surpasses understanding and help me change so that I may lead a life that is pleasing to you. I want to go to heaven and I want to be called by the Fathers name. As of today I declare that I belong to you". Amen If you do this with all of your heart you will start noticing subtle changes inside of you and step by step your life will change. I am speaking from experience.