Tenant that won’t leave an inherited house

[Richard Perez]

My wife’s mother recently passed away and inherited her house via a lady bird deed, along with her 2 brothers. The house had 3 tenants living in it, paying rent to her mother on a hand shake deal to rent out a single room each. Between the siblings, they decided one brother was going to move in and buy out the other 2. That brother then went to the house and gave the tenants a verbal notice that they would have through end of February to vacate the property (this was at the beginning of January, momma passed away at the beginning of December). One tenant has left, the other is planning on leaving this next coming week, giving no problems whatsoever. Here’s where things get tricky..

The third tenant first said she would be out by end of January, and then gave an excuse why she hadn’t left. Then she said she would be leaving a week later once the new place she was moving into was ready, but still no movement from her. Mind you this lady has not paid rent since before my mother in law passed (November). Given the excuses, the way she’s been calling one sibling after another, and the way she’s been playing the he said she said game, we felt she was trying to figure out a way to stay. My wife, tired of the tenant taking advantage of the kindness to let her stay so far, told her via text that since the rent had not been paid since December, she must vacate by the next week, Wednesday, 2/14 (sent this message on Saturday 2/9). The lady refused and said have the courts send me a notice to vacate. 

My questions: does the text message constitute written notice to vacate the tenant? There is no lease or contract that the lady has to even be living in the house at this point. Second, how do we proceed to make sure we don’t end up with a squatter situation?