I'm sad for the PP who found out what had happened in The Archers by seeing this thread title. It's not a Spoiler as episode already broadcast and it has been everywhere, but still sad for that listener! If you were an Omnibus listener, you would t know you had to listen live this week as Sunday's episode came on so suddenly.
And I also agree with Wannabe's post pages back about Helen actually being guilty. The stabbing wasn't proportionate or justified, unless we hear more details of what actually happened as the grunting wasn't clear.
Also- do we know Henry actually witnessed the stabbing? When Rob shouted at him ("come here you little...") before he was stabbed, did Henry turn and run off not seeing what happened next? It would go a little way towards explaining why he wasn't upset and bought the line about Daddy having a rest on the floor.