But he is seeing the message when he starts the database, not when he does initdb of it.
Hmm, on my machine:
/usr/local/pgsql10/bin/pg_ctl -D pg100/ -l logfile start waiting for server to start.... done server started
But look inside "logfile".
/usr/local/pgsql10/bin/psql -d postgres -U aklaver -p 5472 psql (10beta1) Type "help" for help.
postgres=# \du
Right, the database starts. pg_ctl just can't prove it started, because it doesn't know how to connect to it.
Correction, it can prove it started, because when it connects as the wrong user, it gets an error message which it would only get if the database is up. But in the process, it leaves a message behind in the server's log file.