Ok, Trying not to focus on what XH does - but it's very hard.

He turned up unannounced at D17's workplace today (she is a checkout operator).

Handed her the latest iPhone (value $750) and apologised for his recent bad behaviour.

True to form for him. A violent spew, a guilt gift and an apology.

S15 got nothing (even though he was the one who had actually asked for a phone when he saw XH recently).

He is upset and feels the unfairness - which will probably emerge as conflict with his sister.

XH thinks D17 is easier to win over than S15 (who is upfront with his opinions of his dad's behaviour).

In the meantime, XH is a week overdue in paying his child support. And refused, on the weekend, to contribute to D17's medical specialist bills or to S15's school book order.

Is there anything to do other than sit back and take this?