My husbands sister has only POA over finances with their mother, and says my husband cannot bring their mother into our home to live with us, their step father just passed away, and im not sure where to start, we want her home with us, and the sister is saying we will have to go to court, only because she is wanting $$$ We want her to be around family and loved, because when she finds out her husband is gone, she will not be alive much longer either. HELP
Social Security does NOT pay for nursing homes, unless you meant your MIL is self-pay and the SS is part of the payment, along with the pension.
If your Mother-in-law is getting Social Security and her late husband's pension [if the company had set it up so that the remaining spouse does receive it, some don't due to cuts] she might not be able to be accepted by Medicaid, which is a State program to help elders who are poor.
Others here on the forum will be writing their answers. So please read them and take note on what they are saying. Many will be saying moving Mom into your home from a nursing home is not a good idea.
Since your Mother-in-law has dementia, she might not understand that her husband had passed away. Please study up on Dementia. Scroll to the bottom of this page to the blue section and click on ALZHEIMER'S CARE... there will be many articles regarding the different phases of Dementia. This will not be easy. Both you and hubby will be overwhelmed and exhausted before you know it.
Are you and your husband capable of doing the work for 3 full-time caregivers per day? Usually in a nursing home, a patient has 10 people helping them per day.... doctor, nurses, aides, housekeeping, kitchen help, wait staff, maintenance people to fix things, the list goes on. Or would you be hiring help?
You would also have to remodel the house to make it into a mini-nursing home. If mother-in-law is in a wheelchair, doors would need to be widen to allow the wheelchair to go through.
A hospital bed would be needed, maybe a portable toilet, the bathrooms would need to be made safe with grab bars and if MIL cannot get into the tub, then the tub needs a cut out or remodeled into a walk-in shower. There are so many things to think about when bringing home an elder from a nursing home or even an Assisted Living facility.
Nursing homes are expensive, so I don't understand how your husband sister is wanting the money.... the money pays for the nursing home.
My Dad had around the clock help when he was living at home. It was a whopping $20k per month. Eventually he moved into senior living which help cut the cost by half, which included one short shift with his personal caregiver.