Heckling? The guy just shouted a valid question. He did not threaten anyone or do anything untoward such as throwing objects.
Charles accepted the job of King on live TV with millions witnessing his oaths so the proverbial buck stops at his desk. He can't put out PR whinging that his mum didn't deal with it a full three years after her passing, especially since it was KC3 who recklessly allowed Andrew and Sarah to slither back into family events.
Live and direct feedback from those who live in his Realm may finally provide KC3 a sense of urgency to deal with his awful brother Andrew.