What the parents would have done or did not do is immaterial. The doctor was under a professional and moral obligation to tell them everything about the health of their baby. There is no no greater abomination than abortion but this doctor did not practice up to community standards.
A) We don't know that.
B) they could have given her up for adoption.
C) By deciding to keep her, they should automatically lose the suit. Their keeping their child implies acceptance of the condition and responsibility for its upbringing.