"Equity release is a last resort and does short term good but long term 'bad' for any other relatives."
Unlike spending all your liquid assets on rent for 20 years?
As it happens, I am of the mindset that I would do anything to help my parents.
But there is no need, even, for the OP to sell her house. Many PP have suggested different ways to make the money work so that the parents can have their holiday house, using the rental from their house for that rather than for the OP, for example.
And the long term benefits would be better for everyone.
I would do almost anything for my parents, and them for me and my siblings. But I know they would never ask me to sell their house to reclaim money they had given me years before.
Well maybe to get the lawyer fees to get my Mum or Dad out of an unjust and unbearable imprisonment under some horrible regime abroad, for example, but if that was the case they wouldn't have to ask!
If the OP sells her house now and goes back to renting for 20 years, she will probably never get in the property ladder again. House prices will have gone up, she will have fewer years to pay a mortgage, and any inheritance her parents might have left could have been absorbed into care fees etc (and why not - the money is primarily for the parents and their needs in old age).
The money was given, and the disadvantage to the OP disproportionate in the context of her home v a holiday home.
I note that while PP have been outspoken, the op has not spoken badly of her parents, just her distress at the situation.