The form of the salam in the tashahhud: is it addressed directly or in the third person?

The Shaykh : ... When he reached the point where the Prophet (peace and blessings be upon him) taught him the salam in the tashahhud, Ibn Mas'ud said, "He was among us, so when he died, we said, Here is the point: we must receive the Book and the Sunnah in light of the understanding and application of the righteous Salaf. Anyone who looks at this hadith, and the hadith of Ibn Abbas, and the hadith of Aishah, and the hadith of Umar, will see that they all revolve around the Messenger of Allah (peace and blessings be upon him) teaching his Companions the tashahhud using the form of direct address, But Ibn Mas'ud, who was granted a jurisprudence rarely granted to any other Companion, let alone those who came after them, was therefore keen to convey his knowledge to the Tabi'un among his followers. So he inserted this parenthetical phrase after conveying to us the teaching of our Prophet (may Allah's prayers and peace be upon him) that we should say in the tashahhud, meaning with the "kaaf" of direct address. He then added a clarification for our benefit, saying, "He was among us," meaning he taught us to say, and the Messenger of Allah (peace and blessings be upon him) was alive. When he passed away, Ibn Mas'ud completed this phrase by saying, "When he passed away, we said, 'Peace be upon the Prophet.'" Thus, we take the teaching of the Messenger of Allah (peace and blessings be upon him) to say "Peace be upon you" with the condition that he was in his lifetime. That is, this ruling was specific to the Companions of the Prophet (peace and blessings be upon him) and the condition of his life (peace and blessings be upon him). When he passed away, his Companions said, Had it not been for the clarification of Ibn Mas'ud, we would have continued with the first teaching. But when the clarification of Ibn Mas'ud came, and that this direct address was specific to his life (peace and blessings be upon him), we changed the salam from the "kaaf" of direct address to "Peace be upon the Prophet."