Astrology, which is a pseudo science, has NOTHING to do with ASTRONOMY, which is the study of the stars, planets, and other objects in space. Astrologers are like "psychics" or fortune tellers at the circus. They think they can divine the future by reading the "cards" or by some other "magic" trick. But it's totally false. Astronomers, on the other hand, are scientists- real scientists- who study the planets, stars, black holes, and who search for extra terrestrial life.
NASA is still in existence, although the shuttle program was disbanded in 2011. I know this because I have a relative who works for NASA. He's an engineer and involved in the work to help fight climate change. And yes, Space X, which is a private company, is also very active in developing rockets and other technology.
If your son wants to become an astronaut, then the first thing he needs to do is learn how to FLY airplanes, particularly jet airplanes. And the best place for him to do that is in the MILITARY. The two branches of the service which have made a science out of teaching people to fly are the Air Force and the Navy. If your son has the grades, test scores, and a high enough academic rank to do so, he should consider attempting to get an appointment to either Annapolis or Colorado Springs. And instead of trying to discourage him, YOU should be supporting him. There's nothing wrong with his wanting to be an astronaut. Lots of kids-girls as well as boys- dream of going into space.