My dad is 53 years old with no previous history of diabetes. Should he be concerned with a blood sugar of 131, 2 hours after eating?

Normal. 131 is normal 2 hours after a meal. No need to worry at this time about diabetes.
No. That is a normal post-prandial blood sugar at his age. However, if having any symptoms related to blood sugars or high risk in family history, would recommend a fasting blood sugar be obtained.