I would take dils anger with a pinch of salt. She's angry because her mother got hurt. Perhaps son was meant to ask earlier and forgot. Dil possibly finds the whole situation with childcare being mixed up with family tensions really stressful and this was the last straw for her.
Your son sounds like he needs to grow up. It could be that he feels you prioritise oh over him too much, but he should recognise that the childcare is where you've been prioritising him, he can't have all of you all of the time.
Is it me or am I getting mixed messages