Death is part of life. It needs to be presented to children in this way also.
We start simply, by pointing our things in the environment which haved died – leaves which have turned brown, the ant that you trod on, flowers you cut from your garden which have now died, the road kill we see as we drive along, and even toys which are broken (ie they aren’t working any more). In this way, you can explain the fact that they aren’t breathing anymore, that they aren’t growing anymore. As the events descibed aren’t ‘close’ to you, death can be explained in an unemotional way. Children may want to look at a dead animal – use your discretion, but be aware that they are coming from a point or curiosity and a wish to understand. It is likely that young children will ask questions, in their attempt to understand at their level – answer honestly and simply.
Avoid saying the person has ‘gone to sleep’ as they may lead to fears about sleeping. It’s best to explain that their body stopped working and they stopped breathing.
If you wait to explain death until someone close to you passes away, then there is likely to be a strong emotional response in you, making it harder to explain to your child, and to be emotionally available to them.