Steam cabbage head 8 minutes; cool slightly. Remove 16 leaves from cabbage head; discard remaining cabbage. Cut off raised portion of the center vein of each cabbage leaf (do not cut out vein); set trimmed cabbage leaves aside.
Heat oil in a large nonstick skillet over medium heat; swirl to coat. Add onion; cover and cook 6 minutes or until tender.
Remove from heat; stir in brown rice and next 4 ingredients (through parsley). Stir in 1⁄4 teaspoon of the salt and 1⁄8 teaspoon of the pepper.
Place cabbage leaves on a flat surface; spoon about 1⁄3 cup rice mixture into center of each cabbage leaf. Fold in edges of leaves over rice mixture; roll up. Arrange cabbage rolls in bottom of the inner pot of the Instant Pot.
Combine the remaining 1⁄4 teaspoon salt, remaining 1⁄8 teaspoon pepper, apple juice, vinegar, and tomatoes; pour evenly over cabbage rolls.
Close and lock the lid of the Instant Pot. Turn the steam release handle to “Venting” position. Press [Slow Cook], and use [Adjust] to select “More” mode. Press [-] or [+] to choose 2 hours cook time.