The hibernation advice is good, if the laptop is using hibernation.
Did the laptop wake from sleep in a few seconds, before, or did it take minutes?
Hibernation copies the contents of RAM to a file on the hard drive, and restores RAM from that when the laptop is awakened. It works even if the laptop is powered down.
Normal S3 sleep puts the laptop in a low-power state. The contents of the RAM are maintained, and the PC restarts in seconds. If power is lost, the laptop's state is not restored.
If you're having a problem with S3 sleep, I'm not sure what to suggest.