My sister secretly moved her in-laws into the dream house I spent years working to buy, then told everyone it belonged to her.

I returned home from a three-day business trip to Dallas and found an unfamiliar minivan parked in my driveway, folding lawn chairs sitting on my porch, and a pair of muddy men’s work boots beside my front door.

For one ridiculous second, I thought I had somehow walked up to the wrong house — which made no sense because I had …