Answer

In Jain tradition:

• Subhadrā was the sister of Śrī Krishna and Balarāma.
• Trishalā Mātā, the mother of Bhagwan Mahāvīr, is traditionally described as the sister of King Chetaka of Vaiśālī.

Explanation

If you are asking “Who was the brother of Subhadrā?” — the answer is Śrī Krishna and Balarāma.

If you are asking “Who was the brother of Trishalā?” — the answer is King Chetaka.

Takeaway

So, in short:

• Subhadrā’s brothers: Krishna and Balarāma
• Trishalā’s brother: King Chetaka