So, I recently purchased the Voice of War Pack in Halo 5, and it is amazing. However, my best friend cannot purchase it. You see, our Xbox’s are each others Home Xbox; his Xbox is my Home Xbox, and mine is his. Now, this hasn’t been the first time this has happened, for nearly every Promotional Pack I bought, he has downloaded the pack unto his Xbox, yet it is not available to him in Halo 5. What I don’t understand is that if I purchased it through my account, and he hasn’t, why is it denying him the opportunity to purchase it himself and enjoy it as much as I enjoy the Packs? All I want is for him to share in the fun and have the ability to buy the promotional packs he wants. The best 343 can do is give his account the ability to purchase it in HIS name; but don’t stop there, because I know there might be others out there with this same issues. Losing friends due to them purchasing a pack, while the other is in confusion and sadness on why they can’t join in and purchase the pack. Please help, and make a change; not just for my brother, but for every Spartan out there that has been denied the right to obtain Req Packs.
Hey OP. It’s likely that due to your game sharing and the pack being installed on your friends machine, the store sees it as being installed so won’t allow a second purchase. It doesn’t realise that the license is for another gamertag. What your friend can do to bypass this, is make the purchase from the Xbox store on Xbox.com rather than the Xbox store on the console itself. Can use IE on the X1 in case they don’t have a computer to hand, can be a little clunky but won’t take long to sign in and buy it. Once they’ve done that, they should be able to get their packs 
For other promotional packs, he can also buy them from Xbox.com