My son is an opiate addict (heroin) and has been on/off suboxone a couple of times. I'm not saying that this is what your boyfriend is doing for sure, but if it were my son exhibiting these behaviors I would suspect this: that he sold his suboxone or traded them for Vicodin. When he had the vicodin, he was in a good mood and was calm. Then he realized that wasn't going to work either, so wanted to get back on the subs....but he had sold them...so he had to make up a story to tell his doctor to get a new scrip. (Opiate addicts are often seeking suboxone when they think they can detox themselves. It rarely works for more than a few days.)
When he's not on his vicodin, he is surely going through the inevitable depression and anxiety....resulting in his being moody and argumentative. From what I've seen, suboxone doesn't really help much with these symptoms.
Bottom line is that he's not done yet....and you ARE.
I am glad you are reclaiming your life. It's gonna be a rocky road for awhile if you allow him to continue communications with you....and he WILL want that. Have you considered that? Do you feel able and strong enough to go completely No Contact?
After he moves out, whether he lives with his aunt, his mother, goes in or outpatient, or continues to use...is not your concern anymore. You've chosen to get off the roller coaster so head for the exit signs and leave the amusement park. Life is waiting! (((Hugs)))