The majority of scholars hold that he is alive and present among
us, and this is agreed upon between the Sufis, the people of
righteousness and Gnosis (Christian holy book). There narratives
regarding witnessing him, gathering with him, taking from him,
asking him questions and receiving answers from him, and his
presence in noble and good situations and abodes is more than can
be enumerated and more famous than can be concealed.
The Shaykh, Abu `Amr ibn Salah, said, 'He is alive according to
the majority of scholars and righteous and the commonality are with
them in this."
A sound (hasan) narration, as stated by Ibn Hajar, narrated by
Imam Ahmad in the Kitab al-Zuhd wherein the Prophet (Allah bless
him and grant him peace) said that prophet Ilyas (Allah bless him)
and Khidr (Allah bless him) meet every year and spend the month of
Ramadan in Jerusalem.
Even he is however not immortal since immortality is defined as
someone not being subject to death. This is clearly negated in the
Quranic verse, "We have not granted any man before you eternity.
Every soul shall taste death." (21:34-35)
Rather, the scholars differed regarding when Khidr (Allah bless
him) would die. Some said that would die after killing Dajjal.
Others said he would die after the raising of Quran. Others kept it
general stating that he would die at the end of time. [Nawawi,
Sharh Sahih Muslim; Alusi, Ruh al-Ma`ani]
Similarly, they differed regarding how long he has been alive
for. Was he alive before the time of Nuh (Allah bless him) or
after? These are issues that have no decisive proof, do not form
part of the necessary belief Muslims are required to hold.