I think they only have one car, hvert. OP described the morning and evening routine and they appear to be using one car, so selling it is not an option.

OP - think through the scenario hvert suggested with respect to your own bank account. What is the worst thing that can happen? Locks changed? You can call the police if the locks are changed, I suppose, and they will let you in since you must be either on the title of the house if you own or on the lease if the house is rented out (let) to you. You have your right to shelter and can exercise it. Just do not move out because moving out would backfire later in a custody dispute.