During Knives Out, we learn that
Harlan cut his family out of his will, and left his entire fortune to his nurse, Marta.
His motivation for this, with regards to his family members, can be explained:
His son, Walt seems unsuited for running his publishing company, and constantly pushes for movie rights, against Harlan's wishes.
His other son, Neil is deceased, but presumably the inheritance would have gone to his wife. However, we discover that Neil's widow, Joni, was cheating him out of money for her daughter's education
If we're counting in-laws, his son-in-law, Richard, who is cheating on his daughter, Linda.
However, for Linda he still seemed to care for her based on what we see in the movie with him leaving her a letter telling her about Richard's infidelity and the lack of any conflict shown. So why
did he cut her out of his will?