I agree that he could be labeled as a perfectionist, but the frequent hyperfixations on various different topics, as well as the inability to follow through on

I agree that he could be labeled as a perfectionist, but the frequent hyperfixations on various different topics, as well as the inability to follow through on grandiose ideas point towards ADHD. It's impossible to tell with 100% certainty, his life shows too many common symptoms of ADHD for me to be convinced otherwise.