Tamiflu (antiviral) for sick 11m old who tested negative for c-19 and influenza? Yes or no?

My baby has been sick since Saturday evening. We finally took him to the doctor who suspected he had influenza but tested negative for those two . However his fever keeps coming back. The doc say, she still recommends it but I thought why ?

Anyway should I? It’s Al’s past the 48hrd so not sure if it’s too late anyway.