Complex sentence: After his sons death he gets a job in the FBI, he than started in the Criminal Investigations Division and in 2000 getting a job in the X-Files after the disappearance of Mulder.
Split into simpler sentences: After his sons death he gets a job in the FBI, he than started in the Criminal Investigations Division. In 2000 he got a job in The X-Files after the disappearance of Mulder.