Can DLC be shared along with games with family sharing?

Solution 1:

Yes, you can share DLC with Steam Family Sharing.

However, DLC will not be shared if the "guest" (as opposed to the lender) also owns the game:

Who owns and can access the DLC and in-game content associated with a shared title?

A guest will have access to the lender's DLC, but only if the guest doesn't also own the base game. Guests may not purchase DLC for a base game they don't own. Any player may purchase, trade, earn, or otherwise acquire in-game content while playing a game, but in-game items cannot be shared between accounts. These items remain the property of the account that purchased or acquired them, whether borrowing or lending the base game.

http://store.steampowered.com/promotion/familysharing