From the conversations she overheard She thought they were going to put her into a nursing home where she would be drugged into an easy to handle vegetative state until her estate had been nearly drained. Then she would be allowed to starve and dehydrate to death.
Fear of that would drive just about anybody to do what she did.
“Happy Gilmore” is a comedy but the part about where he has to put his grandmother in a nursing home (and how it’s shown) is quite disturbing.