Explaining hair loss to a young child

[Kris for Julie]

My best friend, Julie, is about to start chemo (Abraxane, as well as continue Herceptin). She's been told she will lose her hair for sure - again. Last time, her little girl was only 11 months old. This time, her daughter is a bright, four-year-old little girl filled with lots of questions about everything. Up until now, she has been oblivious to her mother's battle. (We just found out recently, after three years, that Julie's cancer had spread to her bones). Do any of you mothers of young children have any advice that I can give to my friend? She's still very hesitant to come online, but has appreciated all that I have learned from you wonderful women already! She was hoping that one of you might have some suggestions for her. Thank you, as always, for your thoughts! Kris