In my opinion, it is important to follow the average of the readings taken over the course of the three days. Based on the readings you have provided, the average blood pressure would be around 133/90, which is still slightly elevated.
It is possible for there to be variations between different blood pressure machines, but these variations are usually small and should not significantly affect the overall interpretation of the readings. It is important to ensure that the blood pressure machine is calibrated properly and that the cuff is the correct size for the patient's arm.
Next Steps
As for the next steps, I would recommend that your husband schedule an appointment with his doctor to discuss the results of the blood pressure readings. Depending on his medical history and other risk factors, the doctor may recommend lifestyle changes such as diet and exercise, or medication to help lower his blood pressure. It is important to address high blood pressure promptly to reduce the risk of complications such as heart disease and stroke.