Can Medicaid take back monetary gifts?

I am in the process of applying for Medicaid for my mother. She was admitted to the nursing home two months ago because I could no longer care for her in our home. I have a power of attorney and am joint owner of her checking and savings accounts. Can the nursing home take a Roth IRA, pension, etc.? Do I have to label these as assets? She has gifted almost all of her income in the last four years to the family, but the decision to go to the nursing home was sudden. Can they come back on us and take away those gifts?