Back to Back fevers?

Hello, my friend’s son is 1 years old. In the recent year, her son has been getting fevers back to

back, meaning he’ll get a fever out of nowhere & it’s usually high, like up to 106. He’s been going to the ER because it’s really high and he’s have had 2 fevers that high. The doctor said he has a viral infection. He doesnt seem to be in pain just fussy and whining. He’s also teething, but she said he usually doesnt get fevers when he is, but it’s weird because his last fever lasted 4 days and it was high those 4 days. Now his fever went down to 104. What could this be and any suggestions or natural remedies to help surpress his fever?