u may consult eye doc nearby..there may be infectio/allergy
because of chlorine in the water..if he had been swimming previously also and there were no problem before then it might be an infection ,,u can use ofloxacin
eye drops 2 hourly . one one drops in each eyes ..and keep his eyes closed for few minutes..
one has to check for any foreign body inside the eyes..if problem persist..though its rare but one has to rule out..
please take care of him..and rush to the eye doc..