M.B.
So sorry! Our nearly 3 yr old is like that as well. But with her, the fevers have been as high as 106 and often last a week. We've had blood tests done several times and have seen an immunologist, but have no answers. However, nearly every fever during the last year and 1/2 has been accompanied by a sore throat and swollen tonsils. After several of these visits to her ped without strep, her doc recommended we get her tonsils removed.
When she was a baby, she had also ear tubes inserted after 8 ear infections in 6.5 months. Now we and her ENT have concluded that her tonsils and adenoids are just too big and her ped and I believe her tonsils work too hard whenever she gets exposed to a virus (she's also in daycare).
Obviously, this has been really hard on her and disruptive for us all, so while I'm nervous about the tonsilectomy, I'm very hopeful it will really help her too. I wish you luck with your boy!