I have no idea how to help our kid adjust to his new life with us and my wife isn't helping.

To make long story short, my wife has a 13 year old brother who moved in with us about five months ago. Her mom has a long history of substance abuse (my wife was raised by an aunt) and the kid was finally taken away by social care and was placed with us and I’m pretty sure we’re gonna end up adopting him because unfortunately I can’t see his mom or bio dad getting their act together any time soon.The kid… the kid is a good boy, who has been through a rough time and witnessed things he should never be exposed to, but he’s a bright kid and the first couple of months of having him in the house were fairly easy. I was fast to establish rules and a routine that he felt comfortable with, and I fooled myself thinking everything from now on would be easy and perfect. Nope.Once the first 2-3 months went by, I started to notice a certain change in his behavior. He slowly started to become angrier and more rebellious. Now he just doesn’t listen, he straight up ignores his teachers at school, he gets violent (once broke the door of his closet), and there were a couple tantrums where we just couldn’t stop him from crying and screaming.I try to “get the situation under control” as the therapist we are seeing has instructed, but my wife isn’t helping! The other day, he came home after midnight (curfew is 6 o’clock). We were worried, I had called the police, and we were out looking for him, so naturally when he waltzed in as if nothing happened, I was angry. I scolded him and grounded him because what he did was wrong and almost gave us a heart attack, but my wife started yelling about how “I shouldn’t try to discipline him” and “he’s her brother”, but somebody has to discipline him because she’s not doing it. He doesn’t listen to a word she says, so she just ignores him and lets him get away with everything.To be honest, we are 26 and we don’t have kids of our own (don’t plan to have any for the next decade) and it’s fair to say we have no idea what we’re doing. But this kid has nobody other than us who gives a damn, and if we’re going to be responsible for him, we should do a good job and help him because I can see him suffering and it’s awful.The kid is currently in therapy but I don’t think it’s helping him. He even said he doesn’t like going there. I don’t know what to do. When he’s in a good mood, the two of us get along great, but for the most part he just looks stressed and unhappy. Is that something that will go away with time? Because for now I can’t stand to watch him go through that and feel like there is nothing I can do to help him…At this point, any advice would be welcomed.P.S. Sorry for the essay. via /r/Parenting http://ift.tt/2k3kxpj