Sleeping

Q: Can you sleep at the of asr?

Q: We hear from scientists and doctors nowadays that adults need 6-9 hrs of sleep and teenagers need at least 9 and so on respectively. We also heard about great Ulama and still in the present time who only sleep a couple of hours.

My question is that does Islam have a stance on sleep and do you think we should follow this research?

Q: My son and daughter are small and sleep together in one bed.

At what age should I separate them and place them in different beds?

If I had two sons, would it be permissible for them to continue sleeping in the same bed, even as they get older?

Q: Is it permissible for men to sleep on silk pillows or sit on silk carpets?

Q: Is sleeping after tahajjud permissible?

Q: What are some of the worldly harms of habitually sleeping after Fajr without a valid reason?

Q: Can a person sleep between asr and maghrib? If no, then why? 

Q: Is it true that in Islam sleeping or lying on the stomach is prohibited?

Q: Is it allowed to sleep without clothes as there are many benefits?

Q: When I sleep in my bed, my feet are towards the west which is the direction of the Kabah. So what should I do about it?