The limit set for a patient to attend the congregational Salat (prayer)?

Narrated Al-Aswad: "We were with `Aisha discussing the regularity of offering the prayer and dignifying it. She said, 'When Allah's Messenger (ﷺ) fell sick with the fatal illness and when the time of prayer became due and Adhan was pronounced, he said, 'Tell Abu Bakr to lead the people in prayer.' He was told that Abu Bakr was a softhearted man and would not be able to lead the prayer in his place. The Prophet (ﷺ) gave the same order again but he was given the same reply. He gave the order for the third time and said, 'You (women) are the companions of Joseph. Tell Abu Bakr to lead the prayer.' So Abu Bakr came out to lead the prayer. In the meantime the condition of the Prophet (ﷺ) improved a bit and he came out with the help of two men one on each side. As if I was observing his legs dragging on the ground owing to the disease. Abu Bakr wanted to retreat but the Prophet (ﷺ) beckoned him to remain at his place and the Prophet (ﷺ) was brought till he sat beside Abu Bakr." Al-A`mash was asked, "Was the Prophet (ﷺ) praying and Abu Bakr following him, and were the people following Abu Bakr in that prayer?" Al- A`mash replied in the affirmative with a nod of his head. Abu Muawiya said, "The Prophet (ﷺ) was sitting on the left side of Abu Bakr who was praying while standing."