Thank you for the additional information.
Texas has many protections for the debtor. The Texas Constitution (section 28) and Property Code section 42.001(b)(1) provide that the homestead of a family or single adult is protected from forced sale for purposes of paying debts and judgments except in cases of purchase money, taxes (both ad valorem and federal tax liens against both spouses), owelty of partition (divorce), home improvement loans, home equity loans, reverse mortgages, liens predating the establishment of homestead, refinance loans, or the conversion or refinance of a lien on a mobile home that is attached to the homestead. Other liens are void.
By the way, as to the home itself, there is no dollar limitation on its exempt value in Texas. In re. McCombs, 659 F.3d at 507.
Accordingly, the (potential) debt you describe would not be an exception and, thus, yuour grandmother's home should be protected under Texas law.
In any event, I would recommend consulting a local real estate or asset protection attorney to protect your interests and rights. Good luck to you!