It depends. If this is a primary lung cancer, meaning it started in the lung, it depends on the stage and type of cancer. Early (stage 1) lung cancers can be cured with surgery. At 16, a primary lung cancer would be extremely rare; a metastatic cancer (from a cancer that started somewhere else) is more likely. Some of these can be cured (testis cancer in particular), but i'm sorry to tell you most cannot.
Depends. Metastatic disease to the lung is way more common than primary lung cancer in a 16 year old boy- testicular cancer will be the most common type of cancer that goes to the lung for this age group. Testicular cancer is a treatable and curable disease. However, anything else - like soft tissue sarcoma- would be really hard to deal with when it is involving the lung as it usually will be incurable.
Unusual. Perhaps 90% of lung cancer is smoking related; recent molecular discoveries point to other causes (egfr, alk). However, when a disease occurs outside of usual age, and 16 is very unusual for promary lung cancer, the behavior of the tumor is usally unpredictable, but we follow paths as if it were "regular" lung cancer. I've only seen 1 case in a 30+ year career.