I really appreciate your advice and will not engage with his ultimatums/financial issues from now on using the suggestions you, Denver and others have provided.
H has gone nc since our blow-out around cars on Friday. It's a long weekend here and H simply hasn't bothered to contact the kids at all.
As it turns out, the kids and I have been otherwise occupied - my dad was hospitalised after a bad fall on Saturday, so I've spent most of the weekend in the ER.
Not quite GAL, but it's certainly occupied my time.