Amount of hours that the Prophet (S.A.W) would sleep

Waalakum as Salam wa rahmatullahi wa barakatuhu,

The Prophet (sallAllahu ‘alayhi wa sallam) would sleep in the second third of the night. He would also take a short nap after the time of Fajr set in, until the Fajr prayer, and he would sleep for a little while in the afternoon.

All these would total to around 7-8 hours. Bear in mind that Prophet’s (sallAllahu ‘alayhi wa sallam) blessed eyes would sleep, but his noble heart would not sleep.

وكان نومه أعدلَ النوم، وهو أنفع ما يكون من النوم، والأطباء يقولون: هو ثلث الليل والنهار، ثمان ساعات. (زاد المعاد في هدي خير العباد – 1/ 159)

And Allah subhanahu wa ta’ala knows best.