A quick examination of records on Ancestry.com seems to show that while Wolfort is an actual surname, it seems to be a German rather than an English surname.
Of course the question of why JohnFrances chose the name for his character is not exactly the same question as the etymological origin of the name. It is possible he created it himself for the character. It's also possible he saw or heard it somewhere else and chose it for the character. But no matter which of those is the case, he still could have used it because he liked the fact that it resembled "Wolf Fort".