Is the Messenger's sleep — may God's prayers and peace be upon him — without his heart sleeping, exclusive to him, or can it happen to any righteous servant?

It is apparent that the heart of the Prophet, may Allah bless him and grant him peace, not sleeping is among the unique characteristics of the prophets. It has been said that this is a characteristic unique to him alone, distinguishing him from the rest of the prophets, but the hadiths refute this assertion.