Children grieve just as adults do. Any child old enough to form a relationship will experience some form of grief when a relationship is severed. Adults may not view a child’s behavior as grief as it is often demonstrated in behavioral patterns which we misunderstand and do not appear to us to be grief such as “moody,” “cranky,” or “withdrawn.”
When a death occurs, children need to be surrounded by feelings of warmth, acceptance, and understanding. This may be a tall order to expect of the adults who are experiencing their own grief and are upset. Caring adults can guide children through this time when the child is experiencing feelings for which they have no words and thus cannot identify. In a very real way, this time can be a growth experience for the child, teaching about love and relationships. The first task is to create an atmosphere in which the child’s thoughts, fears and wishes are recognized. This means they should be allowed to participate in any of the arrangements, ceremonies, and gatherings which are comfortable for them.
First, explain what will be happening and why it is happening at a level the child can understand. A child may not be able to speak at a grandparent’s service but would benefit greatly from the opportunity to draw a picture to be displayed at the service. Be aware that children will probably have short attention spans and may need to leave a service or gathering before the adults are ready. Many families provide a non-family attendant to care for the children in this event. The key is to allow the participation, not to force it. Forced participation can be harmful. Children instinctively have a good sense of how involved they wish to be. They should be listened to carefully.
(Source: ICCFA FAQs: https://consumer.iccfa.com/faq)