“Tintin himself is not much of a role model either. In the books (and the movie), he is depicted as quite a young man, appearing not a day older than 16. Where are his parents?”
Although he APPEARS young he may in fact be suffering from a medical condition, specifically hypopituitarism resulting from repeated head trauma.
see:
Cyr A, Cyr LO, Cyr C. Acquired growth hormone deficiency and hypogonadotropic hypogonadism in a subject with repeated head trauma, or Tintin goes to the neurologist. CMAJ. 2004 Dec 7;171(12):1433-4. doi: 10.1503/cmaj.1041405. PMID: 15583175; PMCID: PMC534570.