Is a followup exam after colon surgery necessary?
Yes, he should go in for the colon surgery followup. One of the goals in keeping medical information of the patient -- including former scans and other test results -- is to compare a former state with a current state. Healthcare professionals review these to see any new growths and to chart the growth rates as compared to the prior condition. If nothing else, your husband can feel good about a "clean bill of health" when leaving the office.
My husband was diagnosed with colon cancer back in May, because he wasnt checked enough in the UK we believe it may have been the reason he got the cancer, i strongly advise your husband to get checked when they advise him to as you never know what could grow in such short time, better be to safe than sorry. Good luck.