Ask what they believe, what they think, what they think other people are feeling. Never act as if they will get over it or it is time for people to die especially older people. They may be sad for a lng time if the person that died was someone they loved or expected to love. Children will likely try to protect their parents and may hide feelings that are seen as distressing to their parents. Children may write letters or make something special either for the dead person to put in the coffin or for you about the deceased.
Children have their own explanations about things.
Ask them how they would explain what happened to a friend. Share your own feelings , if appropriate. Don't cover up. Help children to see they are not strange because of their feelings. How they are asked will influence their ability to respond.