I have been watching this thread, absolutely gobsmacked by your mum, FWIW.
"I'm only guessing, but I think she won't have asked my brother as he has children and I don't, so she feels he has more responsibility (which he does, being a dad)."
I just wanted to jump in here because it's a bugbear of mine: your achievements, your choices, your responsibilities and your outgoings are no less real or valid because they are not children.
As a childfree adult, I spoke to my ex about splitting expenses if we were to cohabit with his 1DC who he had 50/50. He suggested a 50/50 split which I refused because I did not agree to paying 50/50 when the household would be three people 50% of the time. He went on to say that as a non-parent, my outgoings were more "flexible" than his. I hit the roof. My mortgage or my other financial committments are not less real because my choices did not include children.
There is no "don't worry, pay another month" clause on mortgages, pensions, savings plans or other financial commitments because one is single or child-free.
Many have covered the fact that one cannot reclaim a gift that was freely given. You have also made legal declarations, made decisions, and spent the money in line with it being a gift. Therefore, your mum's ask is unreasonable anyway. Your aunt can just fuck off, this is not her business.
The bit that gets me (and I hope that you are able to get some clarity on this tomorrow) is:
- Are you certain she has not asked your brother? (I know you have said she hasn't but I have form for stewing over things without all the facts). If she has deinititely not asked your brother:
- Is it because daughters are just expected to be more helpful, more amenable? (this is BS and you need to push back hard)
- Is it because your house is a visible asset as opposed to his holiday & car spaff fest? (the house is your home and no one, least of all your mother, should expect you to give it up or put yourself in financial peril for their whims)
- Is it because she expects a quid pro quo? (She is a functioning, sentient adult who made a financial decision 5 years ago. It is not your duty or responsibility to deal with the consequences of the actions of another adult, even if they are your mother.)
And just in case I was not clear enough before, do not let yourself be brow beaten into believing that asking you for this money back is just more "logical". It is not. She asks either both or you, or neither of you.
And I agree with PP who have said that the correct response is "that 50k was a gift which I have since spent. I am unable to help you financially. I can help you seek advice on downsizing on your current budget."