This requires all family members to go insane.
This is completely random, and is pretty RNG base. Basically keep all 4 characters in the shelter, and do everything possible to keep them all in there.
Don't let them open the door when they freak out,
don't look at family pictures,
don't let the kids go out to play,
Blame someone for stealing food,
read the Mary's diary (Mary Jane will lose sanity),
Don't talk to someone if they are quiet (That person will lose sanity),
Don't give gifts on birthdays,
Steal from others when given the chance too,
DO EVERYTHING to make them go insane!
Note:
If most of the family members are insane or their "sanity is questionable" they will likely turn the 1 remaining family member insane