A 28-year-old man from rural Maharashtra presents to the district hospital with a 3-month history of progressive weight loss, chronic diarrhea, and oral candidiasis. He reports unprotected sexual contact with multiple partners over the past 5 years. On examination, he is cachectic with generalized lymphadenopathy. His CD4 count is 85 cells/μL. What is the most appropriate immediate next step in management?