The ruling on the follower praying standing behind a sitting imam, and the reverse

Regarding the witr prayer, when Abu Bakr led the prayer and then the Prophet (peace and blessings be upon him) came and led the people in the story of the Prophet’s (peace and blessings be upon him) illness?
It is the same as that. During his (peace and blessings be upon him) illness, the Prophet (peace and blessings be upon him) prayed with them sitting, and al-Siddiq prayed with them standing to convey the actions to the people. The imam was the Prophet (peace and blessings be upon him), and al-Siddiq was conveying the actions to the people. The Prophet was to the left of al-Siddiq, and al-Siddiq was to his right. This is the Sunnah: when the follower is with the imam, he is to his right. So the imam was the Prophet (peace and blessings be upon him); when he felt weak during his death-illness, he went out and prayed with the people sitting, with al-Siddiq to his right conveying the actions to the people, because al-Siddiq’s voice was louder than the Prophet’s (peace and blessings be upon him). This is the principle in conveying the actions. The principle in conveying is that if the imam is weak, or if there is a gathering that cannot hear the imam’s words, some of the followers convey the takbirs on his behalf, as al-Siddiq did with the Prophet (peace and blessings be upon him).
Among the benefits in this: if the living, regular imam prays sitting, the people behind him pray sitting, as in the authentic hadiths. And if they pray standing, there is no harm, because the people prayed standing behind the Prophet (peace and blessings be upon him) in the last of his life while he was sitting. This indicates the permissibility of both, but sitting behind him is more preferable, because he (peace and blessings be upon him) commanded that. If the living imam prays sitting, they pray behind him sitting. And if they pray standing, there is no blame, as he (peace and blessings be upon him) did in the last of his life.