if your nan has the right to buy the house she will get a discount i think its usually around 30%, with her age she will not be able to get a mortgage, unless you live with your nan and is on her tenency agreement and have been for more than 12 months you cannot get a mortgage and buy it either.
so yournan would need the whole amount already to buy the house outright from the council, then as long as she doesnt ( and i hate to say it ) " pass on " in the full 3 years following her buying it and the house being solely hers, then u can sell it on again.
do you see what i mean???
yes she has the right to buy her house to live out her days rent free
you or your nan would need the total asking price outright in funds to pay the council for it because she wouldnt get a mortgage
you cannot get a mortgage to buy her house unless you have lived with her and is on your nans secure tenency agreement at the council offices for a minimum of 12m to say u live there
once the house belonged to your nan or you if the above wasnt a concearn, you have to have the house a full 3 years before you can sell it on