Can appreciate your anxiety
The treatment being given to your son is in all probability for a condition called acute rheumatic fever
To be sure about diagnosis we need more information like weather he had joint swellings or pain, did the doctor do an EKG or ECHO,any throat swab test.
The fact that he is still running fever after 1 month & you have not been properly counselled about the diagnosis & management I would strongly suggest you to take second opinion
from another senior pediatrician
& a heart specialist. Is is very likely that the diagnosis may be revised . He needs a detailed physical examination & perhaps more tests.
Please do consider my advice seriously as i am also worried about the boy.
God bless you.