My Son Wwt 65kg Has Typhoid But His Fever Doesnt

my son wwt 65kg has typhoid but his fever doesnt come down after taking calpol750 mg fro 101F then it shoots up to above 103F and after taking meftal 250 one and a half tablet the fever comes down to 101 but not below is the dosage of calpol and meftal enough he is 11 years old