Attic Bathroom Plumbing

[desithebuilder]

I know a few that would call it if not at least rolled up (as I see it is now) which didnt quite show in other posts . However IPC code never allows a flat vent regardless of structural conditions . Mass code I dont know if it follows UPC where some discretion is allowed I think Id let it it go but just dont want to recomend from a sketch to plumb it this way but now looking at what he already has done I think its ok but I cant guarantee his card is getting signed.
I dont want to make thisa too hard on him I wish him well if being inspected , and if not I think function be ok

Thank you gents for all the helpful info.