Looks like toothmarks at the top of the beak near its head. Im gonna say that this is something in the grackle family (However, Im no bird expert). It has a robins speckled breast.
Why not mix the mealworms with a little water so they arent crunchy when you bite into em.(theyre usually freeze dried) Then do the crispy granola thing and see which one it prefers. Not a lot of food. People kill more birds by handling and overfeeding.
You may need some medicated water with an eyedropper.
Can he see? Hold your finger close to each eye and see if it blinks or moves away.
If it cant see, Its gonna be a ward of the state.