I would just monitor the eye blinking. If it comes and goes, then it could be a very early sign of Tourette Syndrome. My son started eye blinking at age 5. Had his eyes tested to rule out anything . . . eyesight fine. It returned a year later, then disappeared. Then, he started with throat clearing (no eye blinking in conjunction with that). Finally, by age 10 he had eye blinking (facial tic) in conjunction with throat clearing (vocal tic) and was diagnosed with Tourette Syndrome. Read up on Tourette Syndrome and just keep a close watch. If someone in your family has Tourette Syndrome, then watch your grandson even more closely because it's genetic.
Blinking and random fevers have been linked with vitamin d deficiency.
Does your grandson get enough exposure to bright sunlight? Everyone should get a minimum 10 minutes unprotected exposure to bright sunlight each day to produce optimal vitamin d.
Obviously some days are cloudy and so it's not always possible.
There's all kind of colds and flu going around. A high Temp. can make your eyes burn. but a high temp should be treated with childrens tylenol or Childrens motrin, if the temp. does go down in 30 mins., I have been told that you can use a dose of the other and continue monitoring. If the fever is not going down, take him to the Dr. or the ER. a seriously high temp. can cause convulsions and be life threatening if it continues to rise. A lower temp. that is affected with a fever reducer like motrin or Tylenol is probably normal for a common illness but not a consistanly high temp. Since, you haven't really said what his temp. is, it really depends on your definition of High. If you're not sure, see a Doctor.
the eye blinking could just be a thing he has picked up and now it has become a habit,my son done it for about six months,i had his eyes tested and they were fine,i put it down to tiredness watching tv,as for the temp he could be coming down with the viral bug that is going around