Supplication when visiting the sick and its etiquette

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that when the Prophet (peace and blessings be upon him) visited a sick person, he would sit by his head and then recite this supplication seven times: 'As'alullaha al-'Azim, Rabba al-'Arshi al-'Azim, an yashfiyak' (I ask Allah the Mighty, Lord of the Mighty Throne, to heal you). So if his appointed time had not yet come, he would be healed of that illness of his.
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it. No one other than Amr bin al-Harith mentioned Abdullah bin al-Harith between Sa'id and Ibn Abbas, whereas al-Hajjaj bin Artah narrated it from al-Minhal from Abdullah bin al-Harith, and did not mention Sa'id bin Jubayr in between.

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever visits a sick person whose appointed time has not yet come and says seven times: 'As'alullaha al-'Azim, Rabba al-'Arshi al-'Azim, an yashfiyak' (I ask Allah the Mighty, Lord of the Mighty Throne, to heal you), he will be healed, provided that his appointed time has not arrived."

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "There is no Muslim servant who visits a sick person whose appointed time has not come, and recites this supplication seven times: 'As'alullaha al-'Azim, Rabba al-'Arshi al-'Azim, an yashfiyak' (I ask Allah the Mighty, Lord of the Mighty Throne, to heal you), except that he is certainly healed."

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever goes in to a sick person whose appointed time has not yet come and says seven times: 'As'alullaha al-'Azim, Rabba al-'Arshi al-'Azim, an yashfiyak' (I ask Allah the Mighty, Lord of the Mighty Throne, to heal you), he will recover."