What happens to an enlightened person after death? Do they remain in undifferentiated oneness forever and never be an individual again? I'm afraid of oneness, it sounds like nothing as opposed to everything and I don't understand. It’s the basis for our whole journey, please help me understand.
Enlightenment is a state of liberation, freedom. That means all choices remain open to you. There is no question or possibility of not existing, or losing any state or feeling one has gained, including individuality. If you want to retain individuality, or even physical embodiment after full realization, that option is available to you. Bear in mind that enlightenment is a state of complete bliss and fulfillment, so whatever the enlightened person does, it is from a state of joy, not fear of loss.