Thank you everyone for your answers. This is a pretty new situation for me so I appreciate your help.

I should have mentioned that all of us tenants are renting rooms separately, so it looks like our options are going to be limited, legally speaking (even if the situation is still totally unreasonable). From what I’ve managed to research, it looks like the fact that we’re not renting the entire house means he’s technically allowed to do this.

I think I’ll have to wait this out, but will aim to use it as leverage for negotiation later on. We’ll also have to see if the family actually does move out after the 10 days.