Will all people with hypertension get hypertensive retinopathy?

I’m glad to hear that your child has recovered well. Short answer: The good news is that most children treated for Kawasaki disease recover fully with no long term complications, and will not need further treatment. The earlier he was treated, the better. Recurrence of Kawasaki disease is uncommon. He should, however, continue to follow a healthy diet, and adopt healthy lifestyle habits to reduce the risk of future heart disease (this applies to all children, not just those who have Kawasaki disease).

Yes: cataract surgery is safe for renal patients. Patients with the additional concern of diabetic macular edema (this is the most common and most important cause of visual decline in diabetic patients) needs more care in minimising the risk of worsening edema due to post surgery inflammation. I routinely perform cataract surgery under topical anaesthesia (no injection around the eye) of eye drops alone, so this is an even safer option for renal patients. I would however suggest that your dad schedule his dialysis session the day before surgery though.