I do not believe that Henry Ford bought war bonds in any quantity. It doesn't come up in any of the 4 biographies I have on him (although that certainly isn't conclusive). Henry Ford was an ardent pacifist, and vehemently opposed American entry into WWII; I can't imagine him funding the war out of his own pocket, especially considering how critical he was of "war financiers."
In addition, Ford wasn't in much of a position to order the purchase of war bonds anyways. He had suffered a series of debilitating strokes in the late 1930s, and had been replaced by his son, Edsel, as president by the time the U.S. declared war, and when Edsel died of cancer in '43 Ford became the "figurehead" for the company, with little actual control. In 1945 Henry Ford retired in favor of Henry Ford II.