Answer:
gregory's father: On the day of Gregor's change, the father only seems concerned about the family's finances, and in the two instances when he interacts directly with Gregor in the story, he attacks Gregor in some way, first when he beats Gregor back into his room at the beginning and later when he throws the fruit at him.
gregory's mother: However, she's old, and she has medical issues that make physical and emotional strain extremely taxing. Over time, the stress of sharing a home with a giant insect proves too much for her. Like her daughter Grete and her husband, Mrs. Samsa ultimately transforms and is relieved when Gregor passes away.