If a 90 year old couple wants to sign over a house and land to their son thinking that SS will pay their nursing home bill, what are the laws concerning this?

It is appropriate to transfer the house for tax and or estate planning purposes. It is considered a fraudulent conveyance if it is transfered to avoid having to use assets to pay for medical care.

There is a 5 year window in which a transfer can be reversed if it is found to be transferred to avoid Medicaid issues.

I would recommend you meet with the skilled estate planning attorney to ensure the transfer is appropriate and that you avoid the potential of it being considered a fraudulent conveyance.