Is it legal to sell a house cheap.

[CaliforniaLeaving]

Heres the situation Mum has a house, too big for her, she wants something smaller but in her 70's doesn't want to buy again.
She owns outright, wants to sell to Dh and I cheap, and then give money to my sibling the same value as our discount on the house (if that makes sense)
What can she do legally. If she passes away do we get to pay taxes on the full value and Bro on the money he got too?
What is she gets sick and needs a nursing home, will we have to sell to pay for it seeing we bought her house cheap?
I don't want her to do anything that will come back to bite her in the butt or put us out on the street.
Can you tell I have no clue about this stuff?

[CaliforniaLeaving]

For us I think the house is valued under stamp duty amounts anyway, butthat is a good thought.

[MrAnchovy]

Any transfer of real property needs to be done through a solicitor, and if the amount to be paid is more than £40,000 an SDLT return will have to be made but I didn't mention SDLT because the circumstances described do not give rise to any concerns. Of course if the situation is different, for instance a sale at undervalue to someone who isn't a relative in return for cancellation of a debt, the advice would be different.