Congrats on your new apt!

Moving, even into a better place, is on the list of what considered "major life stressors" emotions and past feelings can pop up out of nowhere. In all types of group therapies we have been to they talk about being extra mindful and vigilant of symptom increases in any mi during thes times. He is young you said, so angry is a behavior based out of fear. Moving comes with uncertainies. Young ones dont usually have a say and feel like no one cares what they think, so acting out angrily is prob the only way he believes he can get your attention. I think he is trying to tell you he is scared. If you can talk to him at all or other parts he trusts. Ask him why he is so angry about moving maybe and let him know you are scared to but reassure him that about all the good things that not just you but all of you and him in particular will like about your new home. Maybe its closer to stores activies ir something he likes. Maybe you will have more room for a bigger tv or ssounsystem or new gaming console....idk. hope some of that might help.
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"The woods are lovely, dark, and deep
But I have promises to keep
And miles to go before I sleep
And miles to go before I sleep"