RE: Unfortunately, there is no way to confirm this was written be someone who is homosexual.
OK, what does it take to “prove” that one is homosexual?
So to answer your question, he must be brave enough to stand up against the Gaystapo by using his real name. Only then can it be proven these really are the words of a gay man. Otherwise, the argument can be made that they are not the words of a gay man, and there is no way to refute that argument.
I honestly hope these are the words of a gay man, but I am left with uncertainty that they are.