My father is retiring soon, he was born in Mexico came to the California at the age of three, he joined the army and is a Vietnam veteran became a citizen before that etc... My question is, his middle name on his birth certificate is different from the one his mother enrolled him in school with, he enrolled in the army with, and has on his SSI... why my grandma did that I have no idea. Is this going to be a big problem when he retires? And what does he need to do?

I am not sure if it will be a problem when he retires, but after going through the hassle with my grandpas death as much as I hate to make you think about that, a problem could arise there. My grandfathers was wrong on his and mine is also wrong on mine. We had to go to our local courthouse and file a correction form for our birth certificates. A lot of times birth Certificates have mess ups like that because of typos or the writing wasn't perfectly legible. I live in Wisconsin, but not sure where you are from. I would have to say contact your local courthouse or SS office and ask they are always happy to assist you in matters like that.