Disclaimer: I haven't read the novel. But I have read a lot of King's other works. He uses the 3rd person omniscient POV a lot, and tends to "head hop" within individual scenes in a many of his novels. Just to play devil's advocate here, can you give us any clues that illustrate he is indeed giving us the perspective of the son? I'm limited by the passage, so all I know is that there is a narrator describing a woman in a typical Kingsian manner. I'm only asking for clarification because I think a lot of times with King it's easy to get tripped up by the quick and often subtle shift in character perspective. 2nd disclaimer: you're probably right, because logically it wouldn't benefit the writer to use obviously uncouth language if he wasn't already in the head of one of his myriad disturbing characters... but I still wouldn't put it past the old Sai.