SAN FRANCISCO, California - Amy Dowdall couldn't believe her eyes when her 70-year-old ex-husband drove up their driveway in R471 000 Nissan Murano CrossCabriolet with a salesman riding shotgun.If this was any other situation, apart from the choice of vehicle, she would've been delighted but unfortunately her ex-husband suffers from dementia.According to the Petaluma Argus-Courier, Amy is legally separated from her husband but felt compelled to get involved when his health started to decline. He was diagnosed with Lewy Body dementia in October 2011, after undergoing brain surgery and is in the Acute Psychiatric Ward of the Jewish Home in San Francisco. He is not supposed to drive, let alone buy a new car.LEGAL BATTLEAmy immediately explained her husband's medical condition to the car salesman and demanded that the car be returned. However, while the salesman acknowledged that something had seemed amiss with the man, he told her there was nothing he could do since the sale had been completed.Since then Amy, who has power of attorney for her husband, has been trying to undo the sale. In December 2011 Dowdall drove himself to the North Bay Nissan dealership in Petaluma, California, traded in his Nissan Altima Hybrid and purchased a new 2011 Nissan Murano convertible with nearly R76 000 worth of extras and agreed to monthly payments equivalent to about R7000, reports the Argus-Courier.Amy explained: “He never in a million years would have agreed to this in his sound mind.” With the help of a friend, Bob Wahl, Amy left messages at the dealership but didn't hear back. She then hired attorney Michael Baddeley, who wrote to North Bay Nissan in February 2012 asking that the contract be rescinded.Greg Dexter, owner of the dealership, called in response to the letter and told Baddeley he had talked to Wells Fargo, the bank that financed the loan for the car, and offered a settlement. However, he didn't tell Baddeley what the settlement offer was.Dowdall followed up with a Wells Fargo representative, who apparently said she wasn't aware of any settlement offer. Baddeley pointed to a California law that says a person with an “unsound” mind has no power to make a contract and that any contract such a person does enter into is subject to being undone. The problem was how would the dealership know of his condition, as he may of come off as being in good mental health when he made the deal.Baddeley said Dowdall's condition should have been apparent to the salesperson. He pointed to the fact that Dowdall paid for extras without negotiating.POINTING FINGERSDowdall's doctor, Paul Larson, confirmed his “markedly impaired judgment, lack of impulse control, aggressive and compulsive behavior and an almost total lack of insight into his condition” in a formal letter.Assigning blame in cases like this is not always straightforward. Richard Hechler, an elder-abuse attorney, said: “If this guy wasn't declared incompetent, he had the right to do whatever he wanted. You'd think that it would be a good business practice to inquire and make sure you're selling to someone who is properly able to contract."Amy is now considering whether to take further legal action and has told the bank she won't be making the payments.Meanwhile, the new car is sitting in a garage with about 60km on the odometer.