nursiecp said:
The cause was undetermined, my husband had been working late at his day job and no one had even been in the shop in 2 days.
My response:
Then, the answer to your original question is "Yes".
In the absence of third-party criminal conduct, then your husband will ultimately be found responsible for the damages; i.e., the money the insurance company paid to their insured will ultimately come out of your husband's pocket.
You see, when your husband accepted the vehicle into his shop property, he created what is called, in the law, a "bailment". In this case, a "bailment for hire" because your husband was also to be paid for the work he was to perform in the repair of the vehicle. When such a bailment is created, the "bailor" (your husband) must take "great care" to protect the property of others under his possession, custody and control. Since fires do not occur in the absence of either criminal conduct, or neglect. That means that his shop (or something within his shop) was the ignition source of the fire; e.g., a faulty water heater, oily rags, etc. - - all of which can cause spontaneous combustion.
The reason for his liability, in this type of situation, where the ignition of the fire is unknown, but not due to criminal conduct, is called "Res Ipsa Loquitur" - - translated means, "the thing speaks for itself"; the "thing" being the fire. For example, the doctrine of res ipsa loquitur creates a presumption of negligence where plaintiff (vehicle owner) shows (a) his or her injury (the loss of his vehicle) is of the kind that does not ordinarily occur in the absence of negligence; (b) the injury was caused by an instrumentality in defendant's (your husband's) exclusive control; and (c) the injury was not due to any action of plaintiff. Where these elements are shown, the burden of proof on the issue of what caused plaintiff's injuries is shifted to the defendant.
Good luck, but your husband should expect a demand for payment by the vehicle owner's insurance company. If your husband fails or refuses to pay, he can expect to be sued.
IAAL