The pronoun "I", wherever it is used, refers not to an individual human body/mind organism, but to the One Self, Pure Consciousness, God. Enlightenment is simply the realization of this truth and the subsequent dis-identification from the illusory individual self and identification with the One (also known as God).
Certainly the One Self playing the role of Jesus had this realization of itself as, through the body/mind known as Jesus, it said "I and the father are One". Again, this was not the realization by a person, but the realization of the Self by and through an apparent person. God