Here's something ...
Why are you so sure he's got a middle name?
I for one do not have one ... there are many cultures in which one has a first name (a given name) and a last name (a family name) and that's all ...
I for instance do not have a 'middle' name ... we don't call it that ... in Eastern Europe, people refer to others (usually referring to those who are older) by their first name and the name of his/her father (in russian, such is called 'otchestvo' ... not a middle name).
So, I'm not sure that SS even has a middle name if it's not listed anywhere officially.