Can we just use her monies since they are jointly owned?
Joint ownership can be a good way to avoid probate, but many people mistakenly believe this form of ownership will preserve the assets from being counted on a Medicaid application or that the end result will be consistent with the terms of the parent’s will for all the children to share and share alike.
As joint holders of accounts with a child (not a spouse) the key concern by the State is whether or not Mom intended to make a gift and when the gift occurred. For example was a gift tax return filed that would support the claim of joint ownership? Did either of the children contribute any of the monies to the accounts? On the other hand if the parent only intended to allow the child(ren) to have authorization to spend the funds on her behalf and then receive the assets upon her death, the monies will be subject to a Medicaid look back period and possible penalty if you spend the monies other than to benefit your Mom.
There are not enough facts here to give you solid legal advice. Is Mom married? Separated? Is Dad in a nursing home? How much money is involved? Is Mom still competent? What is Mom’s health like? Is her condition permanent or is she in for rehabilitation treatment? How do you plan on spending the monies? Will Mom need these funds for her care? Are there long term care insurance or other assets to pay for Mom’s care? You didn’t mention whether or not there was a financial power of attorney with gifting powers. Questions about joint ownership with children rarely have simple answers. Sit down with a knowledgeable professional before you assume control of these joint accounts and create unforeseen problems.