ISO birth brother born Butte, MT 1964

I am searching for my brother born in Butte, MT 1964 and my mother. Mom must have been about 24 and she let her father care for my brother at times as I understand. She graduated from Montana State University and became a RN. I was born in Las Vegas June 28, 1970. I lived there with my mother and brother until we were separated. Any information would be helpful. Maybe someone went to school with her or something and knows the story. Thank you.