Hypochondriac?

I have a 20 year old sister. She is pretty, but overweight. Very standoff-ish and is a total homebody. Lives at home, does online college classes that requires one day of actual class time. She is ALWAYS "sick" with something. Just lays on the couch and whines about everything. But, when one of her friends calls- she jumps up and is suddenly healthy. This is a 24-7 thing. I am always stuck doing all the chores, since she's always deathly ill. Why does she do this? My mom defends her tooth and nail too and she's never really actually sick. I'm growing tired of it.
Hypochondriac?
Post Opinion