^I explained why Trip doesn't feel he can face his family and friends anymore. Whether that will last remains to be seen, but he does have a reason for avoiding them.
Basically, the previous books kept Trip from "coming back to life" through a series of hard-luck plot twists and misadventures that kept him from returning to his old life as he wanted. I figured that couldn't keep happening forever, so I needed to find an internal reason why he would've chosen not to go back. Given that, by this point, he'd been "dead" for seven years and gone through many traumatic, life-changing experiences, I could believe that he just felt he was no longer the man he'd been and that it was kinder to his loved ones to let them have closure and move on with their lives.