Marasmus vs Kwashiorkor Severe Malnutrition

A 14-month-old boy from rural Maharashtra is brought to the pediatric ward with severe weight loss. On examination, he weighs 5.2 kg (< 3rd percentile for age), has visible ribs and hip bones, loose skin folds, and a characteristic "old man face" appearance with loss of cheek fullness. There is no pitting edema. His mid-upper arm circumference (MUAC) is 9.8 cm. The clinical presentation shown in the diagram as **A** (Marasmus) is consistent with this child's findings. According to WHO criteria for Severe Acute Malnutrition (SAM), which of the following is the MOST appropriate initial management step during the stabilization phase?