It is narrated from Sayyiduna Kulayb al-Juhani (may Allah be pleased with him), who had the honour of companionship, that the Messenger of Allah (peace and blessings be upon him) said: "The eldest of the brothers is in the position of the father."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16499