Children of all ages should be given a choice of whether to attend the funeral. Share with them in age-appropriate ways what they can expect to see and experience at the funeral, wake, shiva, or memorial service. Most funeral homes have options for children such as a special room just for them where they can go if they need a break. Make sure there is someone else who can attend to your child if you know you will not be able to be by their side and give them your attention.
Funerals and other services to mark the death of someone in their family or circle of friends are an important part of life and children should not be excluded. But they always need to be prepared and given choices beforehand and once they get there.