Kids sleeping in same room as brother in law??

Hi everyone, I have a question and wondering if I’m overreacting. I’m a F(30) and have two girls (9 and 6). We are going on vacation and my brother in law (32 years old) is staying at the Airbnb with us. My husband said he will sleep in the room with both my daughters. He is close to them and a great uncle but I feel incredibly uncomfortable with this sleeping situation. As a mom I just don’t feel okay. Even if it was my own blood brother. Can any other mamas chime in if I’m being unreasonable or if it’s valid?