What is the grammatical position of “أَخَاكَ” after inna?

Aḍrub al-Khabar: Ibtidāʾī, Ṭalabī and Inkārī Reports

• The accusative noun of inna, marked by alif
• A nominative mubtadaʾ marked by wāw
• The nominative predicate of inna
• An absolute object