It could possibly be a joint decision between Huw and the BBC for him to leave completely - there’s no indication so far that he’s actually been sacked. I’d imagine for someone of Huw’s calibre, taking a lesser position would be more embarrassing professionally than just walking away, particularly as for all intents and purposes, he’s not done anything wrong.
I’d imagine that Huw is angry that it’s got to this point especially as nothing came of the original issue and the person in question is still estranged from their family. Unfortunately, Huw got himself into that mess knowing full well the repercussions if it did get out.