Verified answer

Everything you download from xbox LIVE and linked to the account which was use to buy the content and they will only work on that profile and other profiles that are on the same xbox 360. So if you have 1 xbox 360 and it has 3 accounts on it, only one account will have to buy something and they will work for other accounts on the same 360 but if you take off or delete the account which was used to buy the content then te content will not work for other accounts.

it will only work if he loggs in and installs it, the game and map pack are registered to his x-box live account so get him to sign in and install them although i dont know if you will be allowed to play it if you are not singed in as him i know you can do this on the ps3 like x-box im not so sure

my advice :P get a play station ;)