Children do move on from death often much faster than adults so do not be too surprised if they quickly seem to be getting on with their lives than you are able to
I disagree. Children often take their cues from adults, so will often not want to bring up a loss for fear of upsetting people. For example I heard the above many times after our loss, so I felt I should be back to normal so learned to hide my feelings very quickly. I also felt I should be supporting the adults, even as a young child.
From my own experience it comes in waves. There’s the initial upheaval and upset, but while you do get back to normal fairly quickly, it hits you at random times, but by then everything is “normal” so you don’t feel you can bring it up again and remind everyone...
Also the one thing I felt is everyone went back to normal so quickly, when my life had been turned upside down. Barely anyone acknowledged my loss, again I think for fear of having to deal with tears and upset. I wanted to tell everyone, yet I didn’t as I couldn’t stand that silence where people just didn’t know what to do and quickly changed the subject.
I would recommend counselling, or a bereavement group, anywhere they can talk about it. It may hit them months or even years later. They may not want to talk to you for fear of causing upset.
Sudden loss as a child is bigger than adults realise. There’s the realisation of mortality, the constant fear that someone may go out, go to sleep, go to the dr and die, and you’ll never see them again. I still constantly worry. It’s left me with fairly major attachment issues.
I think there’s a few childrens bereavement charities, winstons wish? Get the help. Get help long term.