Complex sentence: The Stones'father, Kelly (Craig T. Nelson), is also an architect, and their mother, Sybil (Diane Keaton), a bohemian type who is dealing with the recurrence of a fatal illness, which isn't directly stated.
Split into simpler sentences: The Stones'father, Kelly (Craig T. Nelson), is also an architect. Their mother, Sybil (Diane Keaton), is a bohemian type who is dealing with the recurrence of a fatal illness, which isn't directly stated.