Grilled Halibut, Eggplant, and Baby Bok Choy with Korean Barbecue Sauce

INGREDIENTS

• 4 6- to 7-ounce halibut fillets (each about 1 inch thick)
• 3 tablespoons water
• 4 medium-size Japanese eggplants, trimmed, halved lengthwise
• 4 tablespoons olive oil or vegetable oil, divided
• 2 green onions, thinly sliced
• 2 garlic cloves, minced
• 1/4 cup (packed) dark brown sugar
• 8 baby bok choy, halved lengthwise
• 3 tablespoons unseasoned rice vinegar
• 1/3 cup soy sauce
• 1 tablespoon Asian sesame oil
• 1 1/2 teaspoons minced serrano chile with seeds