Try to remember that it is even harder for children not to have the death of a loved one explained to them. It is better for a child to mourn in the company of family than to mourn alone, wondering, yet afraid to ask questions. As a parent, you can take the lead by explaining that while you might not understand everything about death, you will still try to answer the child's questions as best you can. You know your child best. You will have to sense how much of an answer, and how much detail the child is asking for.
Imagination is often far worse than reality.
You are experiencing your own grief which is intense. There are many decisions and details to be handled. Although family and friends cannot take your pain away or change what happened, they may be a comfort during the first difficult weeks. Children also need a support network. A parent is the most important part of the network.