You don’t say whether she is applying for Medicaid in the community or in a nursing home.
If in the community, Medicaid considers the household income and assets, so there’s no need for divorce.
If she is applying for nursing home coverage, Medicaid usually considers the income and assets of both spouses, but there’s an exception known as “spousal refusal” or “just say no.” Your father can refuse to cooperate, and Medicaid will consider your mother’s eligibility based on her income and assets independently from your father’s. Your father may need to sign an affidavit explaining the circumstances. If he won’t cooperate, your mother or you might prepare and sign the affidavit.
Harry S. Margolis practices elder law, estate, and special needs planning in Boston and Wellesley, Massachusetts. He is the founder of ElderLawAnswers.com and answers consumer questions about estate planning issues here and at AskHarry.info.