FEVER, COUGH AND COLD, BODY PAIN. Now?

PROBLEM : My boyfriend is having fever which is on off. Sometime he's having 102° fever and sometime it's 97°. He is sweating maximum time. His stomach is cramping. He is having cold and runny nose. He is feeling weak. Is coughing but have sore throat. HISTORY : Past : He is suffering from fever, cough and cold, common cold and all these type of since childhood. He had mumps when he was 12. and whenever he sleep in the afternoon, mainly in cloudy weather he caught cold. Even if he stays in water for long time he gets cold. Recent : Body pain and chest pain added recently. He recovered from fever (caused from gas) 3 days ago. OTHER AREA: He often suffers from indigestion. And when it happens his body temperature rises. Bodyache, headache, abdominal pain and nausea are common. MEDICATION : he is taking calpol 650 (3-4 times) and cough syrup, plenty of water and orsl. My question is, what should I do now? How to take care of him In future so he don't  suffer often and that much.