If he does find an underlying condition, the next step would be to treat that problem. Gives various problems, treat asthma to control wheezing or if it's an environnemental, sleeping in the wrong place or with his kids.
CM acted with gross negligence. To treat insomnia without ruling out secondary causes and dealing with the root problem is key before starting to treat patients.
CM knew there were other doctors and stated that he saw IV marks - if the patient does not provide info and the doctor is suspicious, he should try and obtain more information, and if he fails, he should simply refuse treatment.