Will the soul be breathed into the entire body of the deceased or only into part of it when the two angels question him, and will he be lying down or sitting at that time?

The soul is returned to the deceased when he is questioned in the grave, as mentioned in the hadith of Al-Bara' from the Prophet, peace and blessings be upon him: "Then his soul is returned to his body, and two angels come to him and make him sit up, and they say to him: 'Who is your Lord?' He says: 'My Lord is Allah...'" Some scholars have interpreted its return to the entire body, while others to the upper half, with its connection to the rest. Matters of the Hereafter are unseen (ghayb) and one must believe in what has been established concerning them. It is not appropriate to delve into what has not been established.