my daughter had this when she was 4. she was ok and act normal. suddenly her eyes rolled up, unable to respond to me.

it was the most terrified moment in my life.
soon after i learned it was fits,
during that period, she had twice fits, fever was too high unable to control with medicine. i have to put her down, let her saliva drip. sometimes she will pass urine at the same time. after that she will feel tired and wanted to sleep.

my experience how to handle it

when your child got fever, pls touch his feet/hand.. is it cold? or hot?

if it is cold, pls use your hand to scrub and do whatever you can warm back his hand and feet. this is the method we always use and it worked

if it is hot, pls try to get a wet towel, wipe his whole body, take off all his clothing.

while you were doing this, give plenty of water, talk to the child. no sleeping coz sleep may increase the temperature. check the child temperature every 5 mins.

dont worry, your child will be fine. take good care of your wife coz this may scare the hell out of her.. she is pregnant isnt?