One of the features I love about MC Command Center is the ability to add relationships. It allows you to add siblings and parents to desired sims. However, you cannot add cousins, uncles, aunts, grandchildren or grandparents yet. This mod allows you to add those relationships! I use it to add cousins since the game only recognizes first cousins by default.
To use the mod, click on the desired sim and click on the Set Family Relationships Menu. Here, you can add or remove relationships (parents are not included because I couldn’t get the family tree to update the way MCC grandparents and siblings worked).
To Install: Unzip the included package and script files directly into your Sims 4 mods folder.
(Only in English for now, but hope to change for future releases).
Sims 4 Royalty Mod Monarchy Mod