In Jainism, each Tirthankara is traditionally associated with a Yaksha (male attendant deity) and a Yakshini (female attendant deity). The term "Yaksha" refers to these attendant deities.

If you are asking for the name of a "Yaksha" who is the brother of someone ("bhai" means brother in Gujarati/Hindi), Jain texts do not specifically mention Yakshas as brothers of each other in the way human relationships are described. Instead, Yakshas are attendants to the Tirthankaras.

However, if you are asking for the names of some prominent Yakshas associated with Tirthankaras, here are a few examples:

• Gomukha (attendant of Lord Rishabhanatha)
• Mahayaksha (attendant of Lord Ajitanatha)
• Trimukha (attendant of Lord Sambhavanatha)
• Yaksha Sarvanubhuti (attendant of Lord Parshvanatha)
• Matanga (attendant of Lord Mahavira)

If you can clarify your question further, I will be happy to provide more specific information according to Jain scriptures.