“What are her options? Is she responsible for my Grandma's IRS debt?”- Also,there was no estate or probate, everything went to my uncle.”---> In general, tax debt will not truly become the responsibility of the Debtor’s family once the Debtor passes away, but there are some exceptions to this rule. Although it is rare, there are situations that would cause family members of the deceased to feel the wrath of the IRS. If the deceased leaves an estate or an inheritance to his family, it can be seized to satisfy the outstanding Tax Debt. If a family member’s share of the inheritance has already been spent, the IRS may pursue them for the funds. So, when you pass away, you do not want to leave a tax burden for the ones you love. IRS Tax Debt issues are unavoidable, even in death. That being said, tax debts must take priority if you don’t want your family and loved ones to be stuck with the bill. Needele to say, wise tax planning is needed.I guess you may need to contact your tax attorney specializing taxation.