I know that the diagnosis of schizophrenia can come as a shock to people but don’t get too caught up in any given diagnosis (they frequently change over time). The important thing is to make sure his symptoms get addressed and try to help him taking positive steps with his life.
Generally, a diagnosis later in life is suggestive of a more positive outcome than a diagnosis earlier in life - and its actually very rare in people over the age of 40s.
I recommend you get in contact with your Local NAMI office to get their suggestions on local resources for your son to help in his recovery. Also - try to get him to an early psychosis treatment center if there is one close to you - for therapy and medications.