In some states one can be determined to be a house guest rather than a tenant, the former not requiring an eviction. The reasons to believe someone may be a house guest as opposed to a tenant are:
- Not paying rent or a portion of the rent
- Not sharing cost of expenses, e.g. utilities
- The purpose behind the occupancy
Nobody ever thinks of creating a Tenancy at Will agreement with house guests who may stay for extended periods of time. It's a serious problem when people who are relatives or friends decide that they will take advantage of the situation. Here is a case on point in Georgia in
Williams v. State which is related to determining whether the criminal defendant was a guest or a tenant (who needed to be evicted) from the premises.
Williams's occupancy of the shed was conditioned on his having a job; he did not have a key to the shed; and there is no evidence that he paid rent. These facts are sufficient to support the conclusion that Williams was a guest, rather than a tenant, with no legal authority to remain on the property after Smiley told him to leave. The facts also might have supported the conclusion that Williams was a tenant at will.
So this being the case, if you hadn't accepted the money you may have been able to give your sister in law the boot. But once you had, you created a tenancy of some sort, at least it would seem to be the case. So, what can you do?
First, if it's your sister in law then I'd expect your husband to be able to help with remedying the situation. Second, it is your option to file a claim in small claims court which will become a public record. I'm not quite sure what the agreement was but it seems that her free ride ended in February. Even she accepted that she was responsible to pay a portion of the housing expenses going forward. How much responsibility can be left to a court, if the young woman wants to deal with the law on defense and not just on offense. And filing a case means it becomes a matter of public record, which your sister in law may prefer to avoid. Perhaps a discussion of each of your options might yield a written agreement between the two of you. My guess is that she is also trying to buy time and will probably need it. If you can settle your differences on 30 days for her to find a new apartment along with reasonable costs, perhaps you can salvage a bad situation and a strained family relationship. We don't have all the details so don't take my thoughts as actionable legal advice, just thoughts on what could theoretically be done given the facts we are discussing informally. Good luck.