The private funeral at Windsor is obviously very different to the State funeral.
My comment about preserve his childhood has nothing to do with hiding the fact his great grandmother has died... As a previous poster has said that would be some feat if they had managed to keep that hidden. It's about the fact it seems unnecessary for a child to be wheeled out for optics. Particularly when there are so many rules about who walks where/ sits where etc and as someone else said, it's unlikely that he can be nestled between mum and dad for a snuggle if he gets upset or overwhelmed.
At Wimbledon, the weather and heat were unseasonably warm, he was still expected to dress "appropriately" royal... Shirt and tie! That seemed ridiculous to me! I get it prepares him for the life ahead where there is a lot expected of you but, as a mum of two, it was shorts and t-shirt weather for kids not shirt and tie! Sometimes the optics seem to take precedence.
Again in relation to shielding from death, I was raised Catholic and attended many funerals where the coffin was brought home, open casket for prayers for days before, so it's not about hiding death. We openly discuss it, and my 5 year old chats about the fact the queen died, and is going "into her grave" on Monday.