He didn't actually transfer ownership to his wife. The articles say he transferred it to her "as trustee" which means he transferred to a trust over which she serves as the Trustee. The article also says the the house was held jointly, but doesn't say whether she joined in the transfer or not.
Pretty surprising that the NY Times ran with this as a story without something more to indicate that his intent in making the transfer was something other than following the long term Estate plan that the attorney suggested was the motivation, because it does sound like Estate Planning.