I mean, even then, he has a huge road ahead of him. I honestly dont see a reason to let him go more than 4 innings for a while, given his fragility. He's two years from being drafted out of Division I baseball and he's pitching extended relief at Double A. Thats fine, but like, that is still light years away from being an ace or a stud or even a top tier prospect.
I agree with your first point. I think they want to see him pitch every 5th day, multiple innings, and build arm strength this year. 140 innings would be just fine, along with a whole season (30 starts). I'd be very, very happy with that. I really don't care about AA, AAA, or MLB for a bit. While you question the fragility, the stuff is what has been playing well so far. Oh, and for the record, he's not pitching relief in the minors. 4 appearances, 4 starts. They're short starts, though. just 13 innings. Extreme BABIP luck, too (,120).
https://www.fangraphs.com/players/jeffrey-henry/sa3014446/stats?position=PFWIW, he has 3 pitches that grade out at 60 per FG. No wonder he dominates when he's out there.