What should I do about my 5 yr. Olds itchy, red and swollen allergy eyes? Over the counter eye drops don't help. He takes benedrly and zyrtec (cetirizine)

See an eye doctor. There are prescription medications that will likely help. Either an antihistamine, or antihistamine combination drop, steroid eye drops are sometimes used acutely for relief. See your ophthalmologist, ask not only for a treatmen, but a plan - what you can do on your own when your child has an exacerbation.
Eye drops. Try zaditor (ketotifen) eye drops over the counter, and use them regularly, keep him indoors during high pollen days. Consult an allergist, they can give you other treatments too.