Hiya Sunny. I think it's really important that you not let your DH grind the 4-year-old's self-esteem down. I speak from personal experience. I spent my boyhood trying to please my father, but it seemed that nothing was ever good enough. I think he was trying to instill high standards in me, but they were ridiculously so, I see in hindsight -- and his withheld approval inflicted on me one hell of an inferiority complex that I still struggle with.
Make sure he's doling out at least as much praise as correction, and preferably much more ("one aw s**t wipes out ten atta boys," right?).
Bandi, I'm happy to post lyrics and such when I think they're germane -- but it seems like grandstanding just to do it out of the blue.