Revealing mistake: When they are in the hospital and Drake says "We'll go now," right before he says that, the guard on the left side of the door from the view shown flashes a small grin.
Continuity mistake: Drake is making a peanut butter and jelly sandwich in the opening scene of the show and squeezes jelly onto a slice of bread. In the next shot, the slice of bread is clean again, and in the following shot, has jelly on it again.
Chosen answer: Well, she is the most liked sibling, so she can probably get more out of her parents, or get money from both of them without the other knowing, or as we saw in the Gary Grills episode she can get money from people easily by telling them all sorts of stuff.