Having trouble controlling my husbands BP he had open heart surgery two months ago. Is this common heart rate ok and INR stable.?

Not commom. But not cause for alarm either. BP can always be controlled. Follow up with his cardiologist and/or primary care doctor until it's controlled. Buy a decent arm cuff ($35-$100) and check his BP after 10 minutes of complete rest each day and keep a diary to bring to the doctor. If overweight, just losing 10% of excess can bring down bp. Avoid salty foods. Google the dash diet. Good luck.
Yes... After heart surgery, the medication dosages are in flux for the first few months. Expect changes in the dosing to be made fairly often. Talking with your cardiologist would be important.