K
Your forum name appears to be your real name, I would advise you to change it to protect your anonymity. See
www.benefitsandwork.co.uk/guides-for-claimants/faq/forum If your sister has ownership in the house even in part then it is treated as capital for the purposes of UC, only the property that you are living in will be disregarded.
Your sister should look at the equity of the house? Is there a mortgage still outstanding? what percentage of ownership does she have? Is the equity realisable?
She really needs to get face to face advice from a trained Welfare Adviser. See
advicelocal.uk/ Gordon