Lucy Highwind was Cid's pride and joy. She was Vincent's best friend.
Vincent was the wise parent. He was the one who provided wise advice beforehand, continuous support during, and sensitive comfort after things went bad.
Cid was the fun parent. He was the one who spoiled her like crazy, let her do whatever Vincent had clearly told her not to, and let her be a part of his adventures.
Some might have called their family unorthodox or strange. But those weren't the people that knew them.
Those that did had never seen a child more loved than Lucy Highwind.