I'm sorry but in order to give a good answer, I'd need more information. Were you and your friend staying the night in the same house together? why did you mention your alter, and why is it important to your question? If you were staying the night together, then he might have just been hearing you talk in your sleep and seeing things in the dark, as shadows can cause illusionary tricks on the eyes.
Also, normally an Astral Projection is an experience that - while sometimes not remembering it, - is still recognizable enough to tell whether you had done one. Dreaming and Astral Projection is quite different, whether you have the memory or not.
Due to the lack of description and, for me and my perspective, slightly disorganized information, I'll go ahead and provide my best estimate and say that your friend's eyes were most likely just playing tricks on him, and the things he heard might have just been mental power or connection between the two of you. For example, sometimes before my mother calls me I can "hear" it and predict it's her before I even look at the phone or answer. I'll also beat her to the punch at times, haha.
I suppose my point is, it might not have been an Astral Projection, but a trick of the night or a general connection sort of experience, assuming the two of you are close or "psychic enough" to experience such things.
This is all personal opinion of course.