Preheat the oven to broil and adjust the rack 3 to 4 inches from the top heat element. Line a baking sheet with aluminum foil and set aside.
Combine 1 stick of the butter, the lemon juice, and Worcestershire in a small saucepan and cook over medium heat, stirring, until the butter is melted and the mixture is warm, about 4 minutes. Pour half of the butter mixture into a small heatproof bowl, add the bread crumbs, stir well, and set aside.
With a pastry brush, lightly coat the baking sheet with the butter mixture remaining in the saucepan. Place the fillets on the baking sheet and brush lightly with the butter mixture. Season the top of each fillet with a 1/8 teaspoon of the salt and a pinch of the white pepper and broil, basting twice, until lightly golden brown and just cooked through, 4 to 5 minutes. Remove from the oven and leave the oven on broil.
Melt 4 tablespoons of the butter in a medium skillet over medium heat. When foamy, add the crabmeat and cook, stirring and being careful not to break up the lumps, until warmed through, about 3 minutes. Remove from the heat.
Melt the remaining 1 1/2 teaspoons butter in a medium saucepan over medium heat. Add the flour and cook, stirring constantly with a heavy wooden spoon, to make a light roux, 1 to 2 minutes. Gradually add the half-and-half, stirring constantly, and bring to a boil. Reduce the heat to medium-low and cook, stirring, until thickened, 2 to 3 minutes. Add the remaining 1/2 teaspoon salt, pinch white pepper, and the crabmeat mixture and stir well to combine. Remove from the heat.
Divide the crabmeat mixture among the fillets, spreading evenly over the tops, and sprinkle each with the breadcrumb mixture. Place 2 bell pepper strips in the shape of an "X" on each fillet and broil until the tops are golden brown and the fish is heated through, 2 to 3 minutes.
Place one fillet in the center of each of four large plates and spoon any additional butter mixture over the tops. Garnish each portion with 1/2 teaspoon of the parsley and serve immediately.