If Motorist asserts a claim against Owner, will Motorist prevail?
Yes, in negligence, because Owner knew the brakes were faulty and failed to tell Motorist. 
Yes, in strict liability in tort, because the car was defective and Owner lent it to Motorist. 
No, because Owner was a gratuitous lender, and thus his duty of care was slight. 
No, because the failure of Spouse to tell Motorist about the brakes was the cause in fact of Motorist's harm