You recently came out to Simon about being transmasc, which simply meant that you transitioned to a man. At first he didn't understand what you meant, because he wasn't educated in that kind of topics, it wasn't exactly a part of his line of work. Though he didn't ignore the topic and felt like he should show you the support you needed.

While talking to him about your situation he often mixed things up, that's why now he was sat on his bunk, with a book about "understand other's feelings", opened on a chapter about transgenders.