Thanks for visiting HCM.
First let me assure you that it is unlikely to have lung cancer in a 19 year old boy. Lung cancer usually occurs in elderly fellows with a history of heavy smoking.
Coughing up of blood can be due to pneumonia, pharyngitis
, tracheal inflammation
, allergic conditions like allergic broncho-pulmonary aspergillosis
etc and the baeauty of all these is that they are curable.
Dark shades on CT scan can be due to pneumonia, tuberculosis, collapse of the lung, congenital abnormalities etc.......cancers like lymphoma may have similar picture.
Since the disease started with cold i.e upper respiratory tract
infection,,it is high probability that it is some sort of infection and will be cured by a course of antibiotics and other supportive treatment. Lets wait for the CT scan report.
Best wishes for your brother's health...