Mold spread across our whole living room ceiling?

WOW, you're in a pretty bad spot. from what you are saying about this house belonging to your mother-in-law and renting it out to you and her son when there is an obvious water leak. al i've got to say is she's some piece of work! it's her responsibility to contact her homeowner's insurance about having the repair work done. it is her responsibility to fix the water leak. if you and your husband do not have renter's insurance then it will be your responsiblity to replace any items in your home damaged by the water. I wouldn't worry about having deadly mold, but the insurance company should have it tested and pay for that too