Oh, I have read this fic so many times XD. It's one of my very favourites.

I'm thinking that, all along his wife was still alive, John didn't think he needed to show more, because she was there to give them the love they needed. And sending them away, even if it's to protect them, to me it's the worst thing he could have done to them, refusing them his help when grieving, making them think he can't deal, exactly, that's it - they were too much for him, whatever ~excuse he had to send them away. It's a bit terrible, imo.