You definitely know more about this than I do, so maybe I'm going to offend you by doubting you, but are you SURE he showed anything more than a passing interest in you? Maybe I'm different, but from what I know of ENxPs, most wouldn't lie when asked if they ever liked you.
A girl liked me for a little bit at the beginning of my junior year. I can't say I was trying to "lead her on", but I was very consciously trying to get her to like me even though I didn't like her. I was pretty aware of when she stopped liking me, and I didn't really feel bad. I just wanted to see where it would lead, and I would have said yes if she asked me out. I'm not trying to justify myself, I just wonder if this is what he was doing. I also do something which can be misinterpreted as flirting (though I don't think ENTPs or even other ENFPs do it as much), which is pushing at people to get them to disclose as much as possible, and then stopping when I feel I've made them uncomfortable. I just really like getting close to people and "joining my life with them" if that makes sense. I'm really self-conscious doing this to girls because it can be taken wrong, but maybe he's not.
Anyway, if he really did show an interest in you, I doubt you're "forever in the friend zone". "Forever" is a pretty alien concept to most ENxPs. I'd say there are next to no situations or ideas they'll rule out as impossible.
"Right now he either needs to... etc." I agree that he should, I just think "needs" is a word which doesn't limit ENxPs very well. I doubt he'll come to a conclusion very fast. It'll probably be up to his ex to finalize anything--actually, what type is she?
I don't think I can offer any "real" advice. I'm pretty bad at that. I hope I helped.
Also, I'd be willing to murder his ex, but I don't like cookies very much.