I have been thinking about what should be said to Henwee (yes, I know it's not real! )
But bearing in mind all the poison that Knob dripped into his ear about Helen, perhaps when he next asks why Giddyjack (aka Myson) can see "Daddy" and he can't, someone might just say something along the lines of Daddy was rather unkind to Mummy, which made her very sad and now that Mummy is better the "people" thought it would be better for the three year old sounding Henwee to be with Mummy.
Alternatively of course he could be told various things, such as "the person you call Daddy is not only a psychopathic, narcissistic deluded fuck wit/knob head , who made you put your bunny in the bin,but he is not genetically connected to you, for which you should be grateful, so give it a rest with the silly voice"
PS Sorry, I've not had a very good day and it's probably better to have an Archers rant than try to have any sort of meaningful discussion on other topics!