It was a tad harsh, yes.
But, it does come across as the title suggests a little.
I suppose - should you be in dire straights - his Mother might well help you out. If you appear to be coping just fine - then why would she give you something to balance what she is giving the other?
I can understand why you feel it unfair.
I have many brothers - most live at home still on a heavily subsidised rent, which then end up borrowing back plus some throughout the month - they all are approaching or have gone past 30, work in average to well paid jobs, they dont contribute towards bills or food shopping - they live the life of riley. Yet they are always bemoaning the fact that they have no money. I have been out and making my own way in life for a long time now with DP. I have never begrudged my parents doing what they do for my brothers - its their back, their rod and their money!!!!!
However, in the past few months, things have become v tight for many reasons, and when, due to an unfortunate soup incident, my Dad discovered what dire straights we are in, they have been helping us out here adn there where they can. I am grateful for it. I still dont begrudge the fact that my brothers live the life of riley....as long as they accept they arent getting christmas pressies this year .
I think, Dros, your DP needs to do what he feels is right - if he wants to broach this with his mother then he should do that. However, if he speaks of money etc - he will no matter how he says it, sound spoilt, even though I agree its unfair on yoru DC.
I also think you are better off making more suitable arrangements for emergency childcare.