Hello Your history is very ambiguous because your husband admitted in hospital for high fever and malaria treatment was given and responded ( fever subsided) but recurs or returns after 2-3 days . Duration of fever is not clear ( how many days ) . Such type of fever may be due to these reasons , these includes. 1 Typhoid fever , get in Widal test as well serology test for confirmation. 2 Tuberculosis , as you mentioned that your husband feeling very weak and fever still present ( if duration of fever is 15 days ) , Get in an X ray chest and blood for C B C , E S R ( if very high 70 mm 1st hour , suggestive of any chronic infection including tuberculosis ) . 3 Jaundice , as I have noted in my so many patients that long standing fever is usually due to hepatitis or jaundice , so please get in liver function test for confirmation. However there are so many other reasons as UTI , respiratory infection ,but deal as mentioned above. Good luck.