The oldest son of Antiochus VIII claimed the Seleucid throne by attacking & killing his uncle, Antiochus IX (95 BCE). A few months later, however, he was driven into exile by his cousin, Antiochus X, launching a family power struggle that fragmented the Seleucid empire & plunged it into all out civil war.  Seleucus himself was killed in a tax-revolt at Mopsuestia, Asia Minor.  Each of his younger brothers (Antiochus XI, Demetrius III & Antiochus XII) launched challenges that cost Antiochus X effective control of large segments of Seleucid territory. This twelve year dynastic feud in turn cost all Seleucid pretenders any lasting allegiance from their subjects & opened the door to foreign domination of their once mighty empire.

References: Josephus, Antiquities 13.366-369.
                  Appian, Roman History: Syrian Wars 11.69.

Other resources on line:

• Seleucus VI Epiphanes - Jona Lendering lists biographical data & chronology of events [Livius: Articles in Ancient History].

• Seleucus VI Epiphanes - entry in Wikipedia's web.

This silver tetradrachma minted at Antioch in 95-94 BCE bears a realistic portrait of Seleucus VI on its face, while the iconography on the reverse illustrates his claim to mythic status. The image of Zeus bearing Nike, the goddess of victory, in his outstretched right hand is a convention borrowed from coins of earlier Macedonian rulers. But the  inscription--Basileos Seleukou Epiphanous Nikatoros  ["of king Seleucus, Manifest Victor"]--more explicitly equates the supreme deity of the Hellenic pantheon with the issuer of this coin than any monarch since Antiochus IV. It is an irony of history that this claimant of divine supremacy was dethroned by his own kin & killed by his subjects within months after this coin was struck.

For high resolution images of this and other coins of Seleucus, see Ancient Coinage of Seleucia, Seleukos VI in David Surber's comprehensive ancient coins website: Wildwinds.