Halo 4 limited eddition code troubles

I really need help here. To start off, me and my brother pre-ordered halo 4 we were really excited. Unfortunately our Xbox"s disk drive broke a couple weeks prior. We browwed one from a friend so no problem. After going to the launch we really enjoyed all the goodies halo 4 limited edition came with though we didn’t use the DLC since it wasn’t our Xbox which was ok. Today we got our Xbox back and we were able to put in the DLC code for the limited edittion. We both have two profiles. Now here is where my problem starts. Previously we had bought halo reach wich had a helmet that came with it, it was recon UA. We were under the impression that we could both use the helmet and we did. When we put in the code for halo 4 limited edition content we put it into his profile assuming we both could use the benefits. I was sadly mistaken. I really enjoy the halo franchise and I really enjoy the game but I can’t enjoy the DLC that came with the game. I hope there’s a solution and I hope I’m not asking for to much but I can’t use any DLC I saved money for. So thank you for the time an I can really appreciate the help.