Martha was an accompliace to a homicide.
As much as I wanted Martha to kick the shackles of insecurity, and forget about the crutch that was her cult family. In the end, even if she got help, theres no turning a blind eye that she was an accomplice to a homicide.
Even if she got help, it would have probably come out in therapy that she was part of a murder, and then would have been reported to the authorities. Eventually landing herself in jail for the next twenty years.
Kinda ruins the comeback-kid feel you want to happen in the movie.