I was just recently surprised with an xbox one. Will I have to purchase the DLC again to use it on the Xbox One? and why can't my brother use the DLC while on my 360?
[quote]Will I have to purchase the DLC again to use it on the Xbox One?[/quote]
As long as you have purchased/redeemed the Expansion on your Xbox 360, you will [b]not[/b] need to purchase it again for the Xbox One.
http://www.bungie.net/en/Help/Article/12122
[quote]and why can't my brother use the DLC while on my 360?[/quote]
Is your brother playing on his Xbox Live account on your console? It should work without having to do anything special. You may want to re-download the content by restoring your licenses.
http://www.bungie.net/en/Help/Article/12181