Dr. Lecter wrote:
Ummm, that still was totally an "inspiring ending"...
I didn't quite read it that way. The last line seemed to be a jab at Whip's past mistakes, and as such, a reminder that he still had many broken things he would have to fix. He's sober, yes, but he still has plenty of past sins left to atone for.
Maybe I'm in the minority, and maybe I'm also not remembering the scene correctly, but I took it as a sly, subtle "fuck you" from the son.