If I put my Mom in a nursing home will the state take her SSI?

Babalou is correct. It is the care center that "takes" money from residents, for room and board and personal care. If mother has enough assets and income to pay her way, everyone is happy.

If mother needs financial aid from the government that usually is in the form of Medicaid -- a federal program administered by each state. Mom will be expected to use all of her income to pay her way as much as she can, and the program will cover the rest. She is allowed to keep a small amount each month (varies by state) to cover personal items like haircuts and treats.

What the program pays is determined by the program. Generally it falls short of the going rate that residents who are not on Medicaid pay. Therefore not every care center is willing to accept residents who intend to pay by Medicaid. More nursing homes accept Medicaid than Assisted Living centers do, but that varies by region, too.

So, first, what exactly does Mother's long term care insurance cover? If between it and her income she can cover the total cost, Medicaid is not needed.

Her ss income may need to be used to pay the care center. But nobody "takes" it. She is just paying for goods and services she is using.

You need to read the policy closely to see what sort of care it will cover.

The issue is not really one of "the state" taking her SSI; the issue at hand is that the care needs to get paid for. She is free to use her SSI to pay for AL; if she qualifies as being destitute (usually assets under $2000 and income under a certain amount per month) she will qualify for Medicaid.

Depending upon the state, Medicaid sometimes pays for AL. In that case, her SSI would be seen as her share of the cost.