Could this be an attachment issue? sorry long

Our 14 yr old as has many issues. His therapist at the rtc keeps talking about RAD and attachment. He has never been diagnosed with attacment disorder and we don't think he has it. I have been thinking about it and am no longer sure. He came to us as a foster placement at 2. when he came he had an unusual attachment to his 3 year old brother. They were inseperable. If you took one somewhere the other would scream and cry. They would lay in bed at night and have a conversation in their own language that even their older brother wouldn't understand. As time went on this became more of a normal relationship. We always thought he was attached to us and for several years he was a sweet, happy child. He was always smiling and could entertain himself fopr long periods of time. He is extremely intelligent and until third grade usually followed the rules and we didn't really have any problems with him. He did however have all these adults that he called his buddies and seemed close to. Somewhere around third grade his behavior changed. He started not listening alot,talking back and running away. In 2009 he was hospitalized for threatening to kill himself. He was put on medicine and given counseling and things were bearable until last year. It started in Jan last year with him putting a garbage bag over his head to kill himself because he didn't want to do the trash. When I took it off him he knocked me to the ground and took off. He was hospitalized but only for three days. It just seemed to spiral out of control after that. He steals-ladies underwear is a favorite esp mine, things as simple as pens and markers(which we have more then enough ) to his brothers cameras,ipod,ds ,phones or anything else he gets his hands on. He tries to come between my husband and me-almost succeeded and now gets frustrated because he can't.At first he wouldn't show his behaviors to his dad (he works 12 hour shifts) and blame me saying all I do is yell at him. My husband was starting to believe him until we talked to a couple at church who had been through it and started getting counseling ourselves. Then our son started showing him the behavior too. He has even thrown something at my husbands head while he is driving. He is obsessed with porn- tries to get on computer(we have it blocked), stolen dvd from cousins house, stole my phone and watched porn on it, has had porn magazines in room -brand new that we think he stole but he says a friend gave them to him. He has taken his brothers phone and camera and put pictures on it. Stole an old phone of ours and had a picture of a penis on it and won't tell us where picture came from. He throws and breaks anything around him- the list of things he broke is endless and he doesn't have enough money to replace it all which includes front and back door. He treats me terrible- makes fun of my disability, calls me horrible names, throws things at me to make me fall,rarely listens to me, tells me it is a free country he doesn't have to listen to meand is just all around disrespectful to me. He has no sense of being responsible for anything it is always someone elses fault. He can't understand that his rules are different from his brothers because of his actions. He believes we are unfair to hium and don't like him so that is why he acts up. He takes off alot. It doesn't matter if we are at home or somewhere else he will take off and sometimes we can't find him for 45 min to an hour or longer. Has had police pick him up after taking off when he was to be hospitalized and he though it was really fun to ride in police car. Threatens to kill himself or one of us. Has tried to hurt himself twice. Threatened to burn our house down. Has hurt his brothers by throwing things at them or hitting them. Was hospitalized 6 times last year before going to rtc. Loves being in hospital and rtc. His behavior at school, church, or hospital and rtc is wonderful. Teachers want more students like him. When he started being hospitalized so much last year people were shocked because they never saw him do the things he does at home and thought he was such a sweet well behaved child. He lies about everything. He has already said he didn't take his brothers cell phone and doesn't have it as he has walked down steps with it in his hands. Even now when he was caught by staff at rtc with his brothers stuff he took while home on visit he lied and said it wasn't his brothers someone in school gave it to him. Really believes everything should be about him and if it isn't he will act up to make it be. We are just trying to figure out how to help him but are really lost. He is a peer modelat rtc and handles things so maturally but comes home on weekends and it is totally different. Steals our stuff,runs away, lies, talks horrible to us, throws things etc. Does this sound like maybe he does have an attachment issue? Any input is appreciated.