He certainly did put some effort into that email and I can't find any plagiarized material. It is apparently he is intelligent, although maybe lacking in the experience of knowing when to start a new paragraph. It's also fine if he wants to look outside of AA to find sobriety, AA is not perfect for everyone by any means (unless you believe it to be divine, thats you're own prerogative).
What I'm not sure of is his motivation, I'm not even sure if he knows what his own motivation is. Why does he want this relationship to work so badly? It's only been 5 months and you both are young, why would he simply not continue looking? One explanation is that he simply does not like to "lose". He doesn't want to "lose" this relationship to you, he doesn't want to "lose" his battle with alcohol (thus why he continues drinking), he doesn't want to "lose" his sense of control over the universe.