"Louie was drawing; it was one of the many talents that nobody knew he had, due to the fact that his long and rambling conversations were very carefully steered away from the topic of himself." -Tenne
Mike seems to have the right idea about Louie; he calls him "Loopy" and dismisses everything he says as crazy. And Louie might very well be crazy, too. He likes to talk and talk and talk and talk without really saying anything... then, for no apparent reason, he'll clam up and refuse to say a single word. And it takes a lot of prodding to make him talk again.
The only person who has any control over Louie is Lily. When she's upset, she runs to him to cry, and he breaks out of his usual babble/silence cycle to comfort her. Otherwise, he's as unpredictable as the weather: you know basically what he's going to do, but not how often, for how long, in what order...
UNLESS. If Rags starts talking to him, you know exactly what's going to happen.
And you take cover.