Complex sentence: His brother, Sam (Padalecki), tells him that Bobby has devised a way to locate Lilith, but unconvinced that it will succeed, Dean suggests he live up the rest of his time.
Split into simpler sentences: His brother, Sam (Padalecki), tells him that Bobby has devised a method to locate Lilith. Unconvinced that their plan will succeed, Dean suggests he live up the rest of his time.