He has 4 badges, meaning he defeated Maylene.
You just go south from Veilstone City. No one's blocking the way there. If it is, then maybe you haven't helped Dawn/Lucas. She should be by the warehouse. When you get to the Lakefront, don't go east. That's Sunnyshore and is still blocked. You should head south still til you hit the beach. When you do, go west. Just keep going west and you'll be in Pastoria City. You can battle Crasher Wake there.