How do I get past the man blocking me on route 222?

Before you can go to Sunyshore City, you must defeat the first seven Gym Leaders, defeat Team Galatic in Veilstone City, defeat Team Galatic at the Three Lakes, defeat Team Galatic on Spear Pillar, and battle Giratina.

Hope this helps!

To get past who is now known as "Anthony Brown", you must defeat the first six gym leaders, go to Lake Valor and have some time to look around, then go to Lake Verity and help out Dawn/Lukas and Professor Rowan. After that, go to Snowpoint City through Mt. Coronet(north), and defeat the gym. Then get HM Rock Climb near a cabin on Route 216, and help your friend at Lake Acuity. Then go back to Lake Valor and go in the cave to battle Galactic Boss Saturn, and then infiltrate the Veilstone Galactic Base(not the warehouse, the building on top of the cliff). Now go to Mt. Coronet from Oreburgh City(cycling road) and instead of going straight through, use Surf at the northwestern corner and use Rock Climb at the northeastern corner. Follow this path until you reach a snowy path. Follow this path until you are found in a one way path. Instead of using Rock Climb, turn left and use Rock Climb. Follow this path until you get to the top of Mt. Coronet, where Team Galactic, DIALGA and PALKIA are waiting. You have to battle Mars and Jupiter at the same time, but you are with your friend. Your friend, after the battle, heals your Pokemon and Cynthia appears. Cyrus uses the Red Chain to create a portal to the Distortion World and you and Cynthia go in it together. Free AZELF, UXIE, and MESPRIT as you chase GIRATINA and Cyrus. At the end, you have to battle both of them. Jump out, retrieve the National Pokedex, and then "Anthony Brown" disappears.

Hope I helped