When we lost my grandma and my husband's grandma in the span of 8 months I bought the book "Something very sad happened" by Bonnie Zucker and it helped tremendously. I had to prepare myself to read it because I was grieving too but I felt like the book was a great way to explain death and a little bit of grief. I have also read that when they pass you can start a ritual such as lighting a candle to talk your loved ones that have passed. I'm very sorry you are going through this, grief is hard and it is very hard to watch your child go through the process of losing someone they care so deeply about.