Am I really the cause of my mothers stress and health problems like she claims?

I am 33 years old and still live at home. I work a part time job delivering papers. My mother goes with me. My mother is 72. She has, recently, been diagnosed with two ulcers and a hernia in her esophagus. She found out that ulcers are caused by stress. She and I are always getting into it and argue constantly. She blames her health problems and the fact that I have her go with me to roll and throw papers on me. My father has been trying to tell her to stop going with me that I'm a grown man and I need to do MY job by myself. I tell her that she can quit when I tell her she can quit. My father is now talking about kicking me out of their house so I will have no choice but to get a full time job and survive on my own. I tell him to drop dead and go straight to H E L L. My mother starts crying and I start mocking her and it makes her cry harder and makes my dad even madder. Am I really the cause of my mom's health problems?