There is unfortunately no answer to this question. In the 1950s, Goofy appeared in a series of cartoons that also featured a son, then called "Goofy Junior." In a few of these cartoons, we heard an off-screen voice of a "Mrs. Goofy" character. Years later, when the television show "Goof Troop" was being created, Goofy Junior evolved into Max and Mrs. Goofy was no longer on the scene. Because these are fictional characters, they do not have real biographies and we can only go by what appears on the screen. Perhaps someday there will be another movie or television show that will explain who Max's mother is and where "Mrs. Goofy" went, but until that time, there is no definitive answer. You can find lots more information about all of your favorite Disney characters in our online Disney Archives.