Complex sentence: Hareton is deeply hurt by this, because he views Heathcliff as his true father, and kisses his corpse relentlessly, digging his grave with tears spilling down his cheeks.
Split into simpler sentences: Hareton is deeply hurt by his subsequent death, because he views Heathcliff as his true father. He kisses his corpse relentlessly, digging the grave with tears spilling down his cheeks.