Tell me, maybe someone had something like this. Baby is 4 months old, …

Tell me, maybe someone had something like this. Baby is 4 months old, in August he got sick (phlegm, cough, throat) they treated him, after 3 weeks started coughing again and throat red, they treated again but it didn't help, still coughs and throat red. All doctors prescribed without effect. Can you tell me who treated in such an age?