The Family Matters Trophy/Achievement for The Quarry requires players to kill every member of the Hackett family. In order for players to do this, they will have to make specific choices during Chapters Nine and Ten. This is how to get the 'Family Matters' Trophy/Achievement in The Quarry.
How to kill everyone in the Hackett Family in The Quarry
Kaylee Hackett will be killed by Laura automatically during Chapter Six. If players want to end the curse, they must make sure not to shoot Travis during Chapter Seven.
Killing Constance Hackett
In Chapter Nine, Constance will turn off the lights, sneaking up on Laura. As they fight for the gun, players must succeed in the button mashing QTE to successfully kill Constance.
Killing Bobby Hackett
Killing Bobby Hackett requires Ryan to stay alive. To do so, Ryan must not take the knife out as he will need it later. After running away and hiding from Bobby, succeeding in any QTEs that come in the player's way, Bobby will catch up to Ryan. Once prompted, players must stab Bobby with the knife, causing him to be too weak to fight Chris off later.
Killing Jedidiah Hackett
After players run or hide as Laura, she will come face to face with Jedidiah Hackett. Passing all the QTEs will lead Laura to make a choice to either attack him or run away. If Bobby is stabbed, Jedidiah will die anyway, but players can kill Jedidiah right away during this scene.
Killing Chris Hackett
Regardless of whether Ryan accepts being bitten, he will live long enough to be able to shoot Chris Hackett.
Killing Caleb Hackett
In order for Kaitlyn to kill Caleb Hackett, players will have to have done one of two things. During Chapter One, if players managed to break into the cabins as Abi and get the doll, the doll will make its way to the kitchen. Kaitlyn must then interact with the doll to be able to use it as a decoy when choosing to run away into the kitchen, locking Caleb inside to freeze to death.
The other method involves Abi surviving and making it into the basement. From there, players can get their hands on silver shells by the fusebox. This will allow Abi to give the ammo to Kaitlyn if she chooses to investigate instead of running to the kitchen and being able to shoot Caleb.
Killing Travis Hackett
There are a few ways that Travis can be killed. The first is being shot by Ryan. If Ryan accepts being bitten but Laura shoots Travis in Chapter Seven, Travis will kill Laura. This causes Ryan to be able to get ahold of the gun and kill Travis.
Alternatively, if Ryan refuses to get bitten, then after he shoots Chris, he will die. Laura will survive if she didn't shoot in Chapter Seven. From there, Laura wrestles for the gun and is able to kill Travis.
For players wanting to end the curse as well as kill Travis, Laura must keep Travis alive up until they find Silas. She can refuse to raise her weapon, causing her and Travis to fight and be able to kill Travis.
For more guides on The Quarry, check out How to keep everyone alive in The Quarry on Pro Game Guides.