Who is Lincoln and Ken from A Million Little Pieces and what is their importance?

Lincoln and Ken are the Sawyer Unit Supervisor and Recovery Counselor, respectively. Both men are recovering addicts who come to work at the Clinic after their successful treatment there. Both men are staunch advocates of AA and the twelve steps, and so James immediately clashes with them. At first, they do not believe that James cares about his recovery because he makes jokes and refuses to take their assignments seriously. However, ultimately they come to respect James's strength and stubbornness.