Dear Karla,
Welcome to Virtual Hospice. I'm glad you found us.
I think most experts would recommend telling your child about grandma's illness honestly. We have several resources that can help you frame the talks you'll have.
For children, seeing their loved one without hair can be hard. I know one mom who had her young son help pick out a hat with her. She told him she would be losing her hair and by letting him chose a hat, it gave him a sense of being able to help and a his piece of control over something he didn't want to have happen. I thought it was a great idea.
May I ask how old your child is?
Colleen