How would you explain the change in relationship between Gregor and his family thanks to his transformation in "The Metamorphosis"?
Your original question did not really make much sense, so I have edited it to make it hopefully more understandable, both to you and to me. Well, it is quite clear that Gregor's transformation has wrought significant changes in his relations with his family. Although his sister at first tries to show love and kindness to Gregor, finding him food that he will eat, she later regards him with hatred. It is she that confronts the facts and also forces her parents to confront them as well when she says:
"My dear parents... things cannot go on like this. You may not realise it, but I do. I will not pronounce my brother's name in front of this monstrosity, and so all I will say is: We must try to get rid of it. We have done everything humanly possible to look after it and put up with it; I do not believe there is anything we can be reproached for."
This, of course, is the ultimate betrayal that arguably is responsible for Gregor's death as he faces the way that even the most seemingly stable and solid affections have turned against him thanks to his transformation.
Of course, although it is his mother who is dragged along by the will of the others, his father, from the first day, makes his animosity known towards his son. Note how he tries to crush Gregor. Gregor reflects on the size of his father's boot soles, but not for long:
But he did not dwell on this; after all, from the very first day of his new life, he had known that the father viewed only the utmost severity as appropriate for dealing with him.
Above all, the change in relationship is characterised by the way in which the family celebrate and are happy when Gregor finally dies and leaves them to focus on the future and live a happy life.