Hi Laura
Why would you not live with them now without buying the house?
If your grandparents asked me, I would strongly advise them against selling the house to you.
In theory, you could exchange contracts to buy the house from them when they die or go into a home.
The problem though with our stupid Fair Deal Scheme is that if you give your grandparents a pile of money, they will have to pay their own nursing home costs. If they have a house, the taxpayer will probably pay.
Brendan