@Knk : "For where two or three are gathered in my name, there am I among them." - Matthew 18:20
I too, believe in the power of prayer and God promises us that if we come before him in his name he will be there with us.
Take comfort in knowing he hears you and your family at this time, and trust God, because he can do better for us than we can for ourselves.
I pray for your mom and her surgery, that it goes well and she is comfortable knowing that she has God with her. Let her be overcome by peace that surpasses all understanding and let her know you are here for her Lord. In Jesus' name amen.