Why Does My Mother-in-Law Keep Messing with the Thermostat?

I H A T E how my mother in law is always messing with the thermostat. For the past month she has been complaining how "cold" the house gets. 😑 Its not even cold , it's FREAKING hot in the house. When my fiancé & I get home the temperature is at 85 degrees. & I swell up really bad with heat 😩 I feel like a cow! But I don't say anything because it's their house, not mines I have been living there for 10 months now. But I feel like she might say something. So I just tell Aaron (my fiancé) to go turn it off or even better to turn on the AC. & he does ☺️ he even tells his mom to stop messing with it because that was the reason why she wanted the AC fixed because the house was really hot & now she is cold 🤔 & also tells her if she is cold to put warm pants on & hoodie. Since she is always wearing shorts and a tank top.

P.S sorry I had to get this off my chest