Let the age of the son be \( x \) years.
The father's age is \( 3x \) years (since the father is three times as old as the son).
The sum of their ages is 60 years, so:
\[
x + 3x = 60
\]
\[
4x = 60
\]
\[
x = 15
\]
Thus, the son's age is 15 years. Therefore, the correct answer is option (1).