Hello, My Boyfriend Has Been Sick More Than 5 Times

hello, my boyfriend has been sick more than 5 times in the past year with a cold or/and a sore throat, he always runs a fever so i assumed it is strep throat, today he says he is running a fever and his lymph nodes are swollen. what should our next step of action be? what kind of medication should he take? also why does he keep getting sick?