Accordingly, what oil did the Prophet use on his hair?
So brother you can see that Olive has been mentioned in Qur'an and you can find multiple ahadiths on it. How our beloved prophet PBUH has emphasised on this oil you can imagine the use. So there is a high chance that he could have used OLIVE for his hair and beard and ALLAH knows best.
Furthermore, how many hours did the Prophet Muhammad sleep? 4 hours
Also to know is, how often did the Prophet bathe?
Well from reading the Koran, the hadith and the sira, I would say quite often. Ghusl has to be performed after sexual contact, so with the prophet having the strength of 30 men and doing the round of his wives in one night, Muhammad probably bathed 9 to 13 times a night.
How often should you shower in Islam?
five times a day