My dad is 67, overweight, no exercise... his fasting gluc. is 115 triglycerides 189 a1c 6.1 creatinine 1.2 egfr 67 besides diet/exercise any advice?

You have it right: It would do your dad, and for that matter anybody, a world of good to maintain healthy weight, exercise about 150 minute/week and have a diet low in saturated fats. He should start exercise with gentle walks and increase the intensity as tolerated. It would be good for him to consult his doctor.

Prediabetes: Your father has prediabetic and metabolic syndrome by definition (HbA1c >5.7 to 130/85 mmHg, body mass index >25, elevated triglycerides >150 mg/dL, fasting blood glucose = 110 to 126 mg.dL and other additional secondary criteria. Treatment with Metformin,other medications + life style modification will prevent progression to type 2 diabetes mellitus.

Stress test.: He has some heart risk factors there - age, triglycerides. Before embarking on a good exercise regimen, which should help his issues, I would have him complete a good quality stress test. Otherwise, diet and exercise should help.