Complex sentence: On Earth, Dave Bowman, now an incorporeal being that exists inside the Monolith, appears on his wife's television screen to tell her goodbye, and then visits his terminally ill mother just before she dies.
Split into simpler sentences: On Earth, Dave Bowman, now an incorporeal being that exists inside the Monolith, appears on his wife's television screen and wishes her farewell. He also visits his terminally ill mother just before she dies.