I don't feel like there's a need for a huge suspension of disbelief on him contacting Quinn's mom. He *knows* it's a bad idea and goes to a different department to look up the info trying to cover his tracks and thinking up cover stories for why he was accessing the records. It almost seems like he knows this is crazy but he can't stop himself.
But like I said in another comment I was still cringing like woah. In fact the first time I read it when he goes to her house (Without even calling first? Who does that?) I had to put the book down and walk away to regain enough calmness to find out what happens.