It doesn't sound like he has walked away from Christ, only that church. And perhaps rightfully so, since they blame him for their own inability (read: unwillingness), in spite of claiming Christ as Lord, to get along with one another.

But to answer your question, yes it is indeed possible for even the very elect to rebel for a season. Sometimes it may even be necessary as a reminder to them of how far and how fast even the "best Christian" can fall without complete childlike humility and dependence on God. But God does not allow the truly elect to remain in such a place of rebellion. He chastens those He loves, bringing them back to their place of joyful surrender and peace.