Lou is very easy on getting into schemes, and mostly lets the kids do whatever they want to do instead of watching them. That's exactly why the kids think he is "Cool".
Lou Pickles's early life is unknown, but it is known Lou was in World War 2, and he was kicked out of the army for breaking his leg on his sleeping bag. Sometime after World War 2, he had two children: Stu and Drew. Then sometime in the 1990's he had grandchildren, and he stayed alive even through All Grown Up!