Pitied by dad, coddled by mom, and all but dismissed by her sarcastic elder brother, Helen is a royal mess before Annie arrives.  Her wild behavior affects everyone in the family.

In regards to Helen's dad (the Captain), he pities his daughter enough not to put her away, but is exasperated enough to yell constantly.  In the first scene, Helen fiddles with everything on Captain Keller's desk, finally sending his important papers to the floor.  Her goal?  To get the family to notice her doll doesn't have eyes so it can be remedied.  The Captain's response to this?

Keller:  Whatever it was.  Deprived child, the least she can have are the little things she wants. (14)

In regards to Helen's mom (Kate), her first appearance on the stage is enough to show that she coddles her spoiled, albeit disabled, daughter.  Here Helen is very close to maiming one of the servants with a scissors.  Kate appears and, after a physical struggle, "Kate gives up, and lets Helen keep them" (10). 

In regards to Helen's older brother (James), he is always sarcastic and totally disgusted by Helen, . . . often more by her appearance than her behavior.  A good example of James' sarcasm is his first line in the play (again having to do with the scissors incident):

James:  She only dug Martha's eyes out.  Almost dug.  It's always almost, no point worrying till it happens, is there? (10)

From their next conversation, James is the one pushing for the asylum.

James:  Half sister, and half--mentally defective, she can't even keep herself clean.  It's not pleasant to see her about all the time. (13)

Yes, it's time for some help to arrive.   Enter:  Annie!  (Thank goodness!)