Subvention - relative passed

Hello, my aunt passed away after being subvented since 2009. Turns out a niece (me) & nephew were left her property.
Please can you tell 1)What is the max the govt can claw back from the house? I believe the rules changed around that time. I remember my dad (a heart patient) getting seriously shouted at by the boss of the nursing home to sign paperwork. I came back and asked on here and people said - don’t sign it, so we didnt. Tbh he wanted to get her home again and wanted the house to be there for her. Sadly that never happened, it lay empty.
Solicitor told me to get a valuation and recommended it was on the high side, even though it would mean we would have to pay more fees to him because after the tax would be less.
2)Why is this?
3) I live in the north but have a plot near her house. We were already thinking of putting up something small, could I roll over tax to help pay for this development? People here keep saying, why are you doing that with Brexit, prices will fall there but It’s for emotional reasons, a tie to the area my family have been in for many generations and I miss my dad & aunt.
Any musings you may have would be gratefully received. Thank you.

are you talking about Fair Deal ?

If she was signed up to fair deal and the state had a lean on the property the max they could take is 7.5% per annum for 3 years - so 22.5%

I may be wrong - but this is my understanding of it

I thought subvention was a different thing to fair deal. It preceeded it.