Perhaps he's "walking according to the flesh" these days. Maybe he's a schizo-Christian. Perhaps he never made it past the 29th day. There's all sorts of answers I'm sure we'll be told.
BTW-I see where some feel that after reading the PDL, it's main message is to "serve" God; as if God needs our service. What a distortion of the truth. We are to glorify God. A subtle but distinct difference lost on many today.
My husband just said the same thing last week.
Service, like everything good in our lives, is a result of God's regeneration. It is a sign of our salvation, not a requirement for it.