In order to get the family reunion ending you will have have to get all the pieces of the mirror mask. In order to start collecting the mask pieces you will have to complete Rakan's chapter and collect all the VHS tapes. Refer to the guide below to get them:
*Credit goes to Minxy for the video*
Achievement will unlock for-
Now that you have your VHS tapes, head on over to the TV room near the main entryway. On the shelf to the left of the TV is a VHS player. Each tape that you will play will give clues on where to look inside the house and what to expect while solving its puzzles. Refer to the guide below to solve each of the tapes (timestamps are in the video if you are looking for a specific tape):
*Once again, credit goes to Minxy for the video. Show some love to him!*
Once you have all the pieces, make sure to save your game. Go to the alter where each of the chapter's items are. The mask will be right above each of the progression items. Interact with the mask. Head down to the basement and interact with the wall that leads to the revolver. Once you head through the door, a vibrant cutscene will play and your achievement will unlock!