Spoiler alert: Aliens are real. They are inter dimensional. I’ve seen and communicated with many of them, of many different types. The trouble you are having is that we were born in captivity in an immersive and holographic mixed virtual reality. They don’t have physical space ships, the way we think they would, because we ourselves don’t live in a true physical reality. Our world itself is a product of advanced alien technology. There is no “nature” that you see when you walk in a forest; it is all artificial. If you don’t believe me just listen to that Radio Head song “Fake Plastic Trees.” I am really telling you the truth. So, your “Good” Doctor friend is either just ignorant or is lying to you. I think the latter. If you pursue knowledge long enough, eventually you must come up with answers. If you keep debating endlessly, then there’s something else going on.