Well, I'm sorry but I disagree with you.
IMO the sooner children are exposed to these emotional events, the easier it is for them. At what age do you think they are 'ready' for a funeral?
They will have no preconception of a funeral, presumably. And if their parents allow them to avoid it because of their own feelings, how does that help?
It's perfectly normal to be upset and cry at a funeral. Postponing the experience is just as likely to make it into a huge 'thing' that they will find harder later on.
I am sorry for OP's loss.
However, I can't understand where the element of 'choice' arose.
Most parents would just say 'We are going to grandad's funeral and you may need to have a couple of days off school for it.'
And if a 7/12 year old says they don't want to go, I'd say sorry but it's a family occasion and we are all going.
And then I'd talk about WHY they'd not wanted to go and try to help them deal with any emotions behind it.
It's not helping children to wrap them in cotton wool about death.