What he wrote was trite and superficial with regards to determining his type. Being a shut-in says nothing except that he probably wasn't popular in school. I was the same way for most of my life until college.
His behavior is more stereotypically introverted, but is anything but conclusive. The behavior could just as easily be due to trauma or some other fixation as psychological type. I've known Se and Fe primaries to whom much of what he says about himself could easily apply.