On this website, I do not always get to give good news, and this is one of these times. I understand that hearing things less than optimal is not easy, and I empathize. Thanks in advance for not "shooting the messenger."
He and his father as the owners of the property. As such, they are presumed to be the landlords, and you are what is known as a "tenant at sufferance." This is a tenant who lives at the property for free at the pleasure of the landlord. See SC SECTION 27-35-170. With little notice, they can evict the tenant at sufferance, i.e. you.
However, there is a possible way to get around this, but it involves filing in court. SC recognizes common law marriages before 2011. Assuming one can argue that they were common law married prior to this, what one wants to do possible is to file in Court for divorce/separation. In doing so, one can ask for emergency orders stating that the property was purchased during the marriage with joint money, making it community property.
If so, then his "landlord" rights are overshadowed by the community property argument, and the Judge may enjoin (stop) any eviction attempts until this is sorted out. But this community property argument only comes into play if someone in your situation files in family court, claiming a common law marriage.
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