cells have many structures inside of them called organelles. these organelles are like the organs in a human and they help the cell stay alive. each organelle has it's own specific function to help the cell survive. the nucleus of a eukaryotic cell directs the cell's activities and stores DNA.
I would tell them to tell a trusted adult and use a helpline like nsvrc.org as a resource. Be there to support them during the aftermath as it will take a toll on their mental health.
Some girls can depending when they started