In the lecture before the Friday prayer, a scholar said these following things about Prophet Muhammad, sallallaahu 'alayhi wa sallam:
1. A fly never sat on the Prophet's face. 2. A cloud would shadow the Prophet. 3. Prophet Muhammad never yawned in his entire life. Is all this information authentic?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

With regard to yawning, then Ibn Hajar mentioned in his book Fat-h Al-Baari in the Chapter on Etiquette [Kitaab Al-Adab] that the Prophet never yawned. He said, “Among the Prophetic characteristics is what Ibn Abi Shaybah and Al-Bukhaari reported in At-Taareekh from Yazeed ibn Al-Asamm, who said, ‘The Prophet never yawned.’ Also, Al-Khattaabi reported from Maslamah ibn ‘Abdul-Malik ibn Marwan that he said, ‘No Prophet has ever yawned.’ Maslamah met some Companions, and he was trustworthy. What confirms this is what was authentically reported; that yawning is from the devil.”

As for the saying that a cloud used to shade him, if you mean that it always shaded him, then this is not true. Authentic ahaadeeth indicated that the Prophet used to be exposed to the sun.

In Saheeh Ibn Hibbaan and the Mustadrak of Al-Haakim, they reported that ‘Ali ibn Abi Taalib, may Allah be pleased with him, said:

“I heard the Prophet say, ‘I never wanted to do an act of the people of ignorance except twice; and in both cases, Allah protected me from committing them. One night, I told a boy from Quraysh who was with me in the hills of Makkah, where some sheep were grazing, 'Keep an eye on my herd until I go pass the night in amusement in Makkah like the youth do.' He said, 'Yes.' So I went out, and when I came to a lower house of the houses of Makkah, I heard singing and the voice of the Duff (a tambourine-like instrument without bells) and flute. I asked, 'What is that?' They said, 'So-and-so married his daughter off to a man from Quraysh,' so I was entertained with that singing and sound until I fell asleep, and I did not get up except by the sun touching me. I returned, and I heard the same thing, and I was told the same thing as before. So I was entertained with what I heard and felt sleepy and slept, and I did not get up except by the sun touching me. Then I returned to my friend (i.e. the boy), and he asked me, 'What did you do?' I said, 'I did not do anything.' I swear by Allah that after this, I did not intend to do any of the evils that the people of Jaahiliyyah (pre-Islamic era of ignorance) did until Allah blessed me with Prophethood.’”

As regards flies, a number of scholars mentioned among the characteristics of the Prophet that no flies ever touched his noble body.

As-Suyooti said in Al-Khasaa'is Al-Kubra: “Chapter: flies never touched the body of the Prophet or his clothes.”

Al-Qaadhi 'Iyaadh said in his book Ash-Shifaa’ and Al-'Azafi in his book about the birth of the Prophet that among his characteristics was that flies never touched his body. Ibn Sab‘ mentioned this in Al-Khasaa’is with the wording that flies never landed on his clothes, and he added that among his characteristics is that lice never harmed him...

However, As-Suyooti said in Ash-Shamaa'il Ash-Shareefah, when commenting on the hadeeth narrated by ‘Aa’ishah, may Allah be pleased with her, who said, “He was a human being just like all other human beings, he used to examine his clothes”; he said, “Examining (one’s clothes) necessitates that there is something that harms in general, such as fleas and lice; so the claim that he was never harmed by lice, or that flies never touched him, is overruled, and there is no authentic evidence for it.”

Allah knows best.