In the Pop Up Edition of Back With a Vengeance, it mentioned that Phil was far away from where Ben was fighting Vilgax and Kevin Levin indicating that he still might be alive somewhere.
However he is nowhere to be seen in the episode Voided indicating that he either escaped, died, or was imprisoned by that point.
It is unknown if he had any encounters with Kevin or Vilgax after they became trapped in the Null Void (it is safe to say that if he encountered Vilgax, it is unlikely he would have survived, given their history).
Phil (back during his plumber day) has a cameo appearence in the episode "The Visitor", in Max & Xylene's flashback (which appears to take place shortly after the flashback seen in "Truth") watching Max & Xylene say their farwells.
Phil is the first Plumber shown to have gone rogue, thus making him the first member of the Plumbers shown to be a villain.
Phil is voiced by Robert Patrick who is best known as the T-1000 in Terminator 2: Judgement Day.