He has his own book, It's Jeff, by Kelly Thompson and Gurihiru. It's a Marvel Unlimited one but some of it has been put into a print one-shot. He's shown to be in the care of Kate Bishop or Gwenpool there (it could be that the whole thing is set during Thompson's West Coast Avengers run where Jeff debuted, since they were both on that team).
Of course when Jeff was in Deadpool, Thompson was his writer. Now he's written by someone else, so no surprise Jeff is gone from that book.