Girls, on January 19th my son turned 3 months old! And I would like to…

Girls, on January 19th my son turned 3 months old! And I would like to celebrate, but not because of illness... A friend came with her child, and the child was coughing. In the end - Misha has bronchitis. He cries terribly when I suck out phlegm, give him medicine. Now there's even a purple crying in his sleep, apparently from stress. Can you please tell me how long this disease lasts at that age? What consequences? We are being treated in a private clinic, but I still feel like the treatment is not enough...