The answer to this question is "no". Federal law prohibits a nursing home from requiring a third party guarantee of payment as a condition of a resident's admission. Therefore, a resident's family member or friend cannot be required to guarantee the residents payments to a nursing home.
Many nursing homes, however, use admission agreements which evade the spirit and arguably, the letter of the federal law. These homes use admission agreements which correctly stated that a guarantor is not required, but then claims the party signing the contract is "voluntarily" agreeing to be responsible for the bill.
No person should agree to become a responsible party for a resident's nursing home bills. Such an agreement cannot be required and legally can offer no benefit to the resident. Consequently, a family member must be aware of signature lines entitled "Responsible Party." Often, these signature lines do not define the term "responsible party" but implicitly refer to the fine print of the document, which will contain language making the signing party responsible to pay for the nursing home bill.
Furthermore, a person who has signed as a financially responsible party should not assume that he or she is financially responsible for the resident's nursing home bills. Such a voluntary promise to pay is unenforceable, because the nursing home promises nothing in return for the financial guarantee. In addition, any voluntary guarantee should be unenforceable because it is grossly unfair and unconscionable.