A 38-year-old male worker in a textile mill presents to the occupational health clinic with a 6-month history of progressive dyspnea, dry cough, and chest tightness. He has been working in the carding and spinning department for 12 years. Chest X-ray shows bilateral lower lobe predominant reticular opacities. Spirometry reveals a restrictive pattern with FVC 65% predicted and FEV₁/FVC ratio 0.82. He denies smoking. What is the most appropriate next step in management?