Possible Clues:

• Work late, producing a sonata
• Beethoven's Op. twenty seven/two sonata
• Work on the side to produce liquor
• Steerer of boat
• The doctor on one of 4 down, but not by the day
• Illuminating reflections on Beethoven's work
• Reflected illumination
• For this there's a son at never by day
• Secretly work
• Doctor performing easy work unofficially