Sayyiduna Abdullah bin Abbas (may Allah be pleased with him), regarding the saying of Allah Almighty: "And whoever is poor, let him eat according to what is reasonable" [Surah al-Nisa: 6], said: The guardian may take enough to satisfy his hunger, may take clothing from the orphan's wealth to cover himself, may drink the surplus milk and ride the surplus mount; then, if he later becomes well-off, he should repay it, otherwise it is lawful for him.
Ubaydah, Mujahid, Sa'id bin Jubayr and others said that he must repay it, while Hasan al-Basri and Ata' bin Abi Rabah said that he need not repay it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11002