@acquiescence
I'm just so so sorry to hear this. 😭
It's a good question. I think they were so consumed by grief it was hard for them to think about what might help. Also it was the 80's so maybe children's experiences were less listened to. Saying that, my mum was a counsellor so she knew and valued the importance of that. I'm pretty sure I didn't have any but I think things that would help are;
Grief counselling for the child. (I heard Winstons Wish can be good for resources- you've probably heard of them.)
Certainly remembering the sibling and maybe trying to include them more eg making a cake together on their birthday. - sort of trying to make the transition from sibling to no sibling a bit gentler...
Letting the child talk freely about what happened.
He would come up in conversation but almost always accompanied by my mum crying (understandably), so I think that meant I maybe didn't talk as much as I might have.
When I look back, my overriding feeling is of us all in separate worlds. My Dad had to keep working, my mum said she'd drop me at school then come home and collapse. We didn't have any other family nearby. I would say if you can, try to make as much family time as possible so your son feels safe in the middle of your family, however small or big it is.
I would say though it really didn't feel devastating to me as a child, it was all I knew and kind of thought that sort of thing happened to everyone.
It's the most devastating thing in the world that you are trying to navigate here, I wish you and your family a huge amount of love and strength.