Since I'm not sure what I have to say will be received well.
I can start gently though with a suggestion to get the book -
Transforming the Difficult Child: the Nurtured Heart Approach by Howie Glasser
http://www.amazon.com/exec/obidos/ASIN/0967050707/nurturingourspir/104-8601410-3224700
His website is at -
http://www.difficultchild.com/
He is from AZ and his methods are being used extensively in the Tuscon area in elementary classrooms. His approach is easy to implement with all types/kinds of SK and the methods do work. The most interesting part of his approach is that it does work in families where there are multiple SKs or even one SK and non-SK sibling(s). He is a well respected advocate and is spoken highly of in social work circles.
As for the discipline thing (and here's where it gets a bit dicey), I can't see how your DH's approach is successful at all. In fact, I can't see how either of you can even say it is successful. Blunt, but baby, time outs for 2 HOURS?! Not a success in my book.
Getting tougher isn't the answer as it will set up a power struggle scenario. Even with the compliance to your DHs style, it still isn't any better since there will come a time and probably sooner rather than later that this will really impact the relationship the two of them have.
The point of raising kids isn't just getting them through childhood alive, but instead helping them to manage their personalities, needs and weaknesses successfully into adulthood. What does "getting tougher" actually teach them? What does a 2 hour time out teach them? At what point does your child begin to internalize the "consequence"? What do you mean by getting tougher?
And by way of an explanation, I don't dispute that there are times when it simply is a punishment and must be forcefully and intentionally delivered...but there HAVE to be other tools in one's parenting bag that should be used as well.