No... maybe...
Sleep mode is a very low power state where only RAM, the CPU, and a few essential devices are powered up. But while the CPU is receiving power it really can't do much of anything, including running programs.
There might be a stand alone application to "wake up on LAN/WAN activity" then customize the app for activity on the MC server port to wake up. However thats just a shot in the dark and never tried this before as most servers I work on stay active.