Sayyiduna Anas (may Allah be pleased with him) says: The Prophet (peace and blessings be upon him) led the funeral prayer of his son, Sayyiduna Ibrahim (may Allah be pleased with him), and said four takbirs over him.
Abu Ya'la recorded it. Its chain contains Muhammad bin Ubaydullah al-Arzami, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجنائز / 4180