Beautiful Boy question

WOW, I love this book! Continuing our discussion of Nic's eyes; the father is repeating endlessly how he sees Nic's feelings and emotions through his eyes. I think that is really special. They have a really special connection and he can look into his sons eyes and "know what is going on" but does he really? Has anyone one else seen this repetitiveness regarding the eyes or anything else? Why did David Sheff chose to repeat himself?