In Mahabharata, Bhishma told that one should wake up at Brahma Muhurta.
Does rakshasa follow that? If not, provide an example that rakshasa won't follow proper sleeping times.
Are there any specified timings for rakshasas to sleep?
According to Bhagavad Gita 16.7, the Asuras don't (usually) follow rules pertaining to Dharma like Saucha (cleanliness), righteous conducts (SadAchAra) etc etc.
Pravrittincha nivrittincha janA na vidurAsurAh |
Na saucham nApi chAchAro na satyam teshu vidyate ||
The Asura kind of person knows not Dharma-Adharma (Pravritti-Nivritti); Cleanliness, righteous conducts (AchAra) and truthfulness (Satyam) do not exist among them either.
So, it is highly unlikely that they will follow such rules/conducts pertaining to Dharma (like getting up at the right time or eating foods that are prescribed to be eaten etc). But unable to give any precise examples of Rakshashas and their lifestyles though.