Talk to Eye Surgeon on Blurred Vision After Glaucoma Surgery

My father was diagnosed with glaucome almost a couple of years back. He has been using the eye drops to control the glaucoma since then. Recently his doctor advised him to go for a surgery. My father's vision got blurred after the surgery. There were some complications in the surgery as told by the doctor and so he had to operate 3 times to remove the complications. The blurred vision did get better but its still blurred. After my father's recent checkup with the doctor, the doctor told us that he has now got cataracts in the same eye. So another operation is needed to remove that and then lenses will be fixed in the eye to remove the blurred vision. I wanted to ask if this is something that happens sometimes with glaucoma surgery or did the surgery go wrong?