I am a long-term steam player with all content unlocked, but I also own all expansions up to and including Final Shape on Xbox, where my son has recently started playing together with me by taking advantage of game sharing. Now I want to buy Year of Prophecy on Xbox, so that he has access to the latest expansions, but I want to make sure that his account is the one that gets the season pass, since I already own it. If I buy the expansions on my Xbox account and launch the game with his account first, will the season pass unlock for him? If not, do I have to gift him the expansions for it to work? In that case, will all the other content still be unlocked for him through game sharing, even though the older expansions are owned by my account and the new ones would be owned by his?