HI My Son Has The Flu - He Is 7

HI my son has the flu - he is 7 he has been fighting a fever since Tuesday, its now Friday and still has a fever its not ridiculous but its still there, he has a very very bad sore throat was checked for strep which is negative, also has a cough this morning he was sweating a lot which I thought the fever was breaking, this afternoon he was ok no fever eveing arrived fever came back . is this normal? especially when he was sweating earlier today?