A 3-year-old boy from a rural village in Odisha is brought to the primary health centre with a 6-month history of poor weight gain, recurrent infections, and generalized oedema. On examination, he weighs 10 kg (expected weight for age: 15 kg), has pitting oedema of both feet, sparse hair, and hepatomegaly. Serum albumin is 2.1 g/dL (normal >3.5 g/dL). His mother reports inadequate dietary intake due to poverty. What is the most appropriate immediate next step in management?