If i retrieve my friends acount and dwnload the dlc and do the transfer online on xbox.com does his still work?

idk wat exactly you are asking, but DRM is very strict. If you download it, and get his account, and get his dlc, it will not work unless you are playing on his account. The DLC is strictly on his account, and his will still work if he just recover his account. but even if you still have the dlc on your harddrive it will still not work, but there is a rights base or something in the harddrive that dis allows you from playing dlc on a different xbox without the account. ITs all very coplicated.