deed fo gift

[katakase1]

hi, My Mother-in-Law inheritanced a house from her dad + Inheritance tax as well. But few years later she had a stroke and she did "deed of gift" (house, 3 years ago) to her son and me. She owns the flat where she lives as well. At the moment she isn't able to pay hers dad remaining tax and even her own depts.
Question:
* Can she sell her flat and pay the depts. Is it possible that she would moves live with us again without losing the "deed of gift" - she start pay the rent ot something else?
* If she doesn't pay the inher. tax is the house reliable for the depts even "deed of gift" and that she has a probpery herself. What will be sold first covering the depts?
Thank you in advance

[katakase1]

Sorry, but I forgot to ask that if she doesn't think to find any money at all for her payment and taxman step in - witch property will be sold first - her flat or the house that has a deed of gift.