According to Jain tradition (especially Digambar granths):

• In the next time‑cycle (next avasarpinī / utsarpinī pair),

• Both are sons of Bhagwan Rishabhdev (Ādinath) in this current avasarpinī.
• In the coming cycle, they will take birth again (with different parents etc.) and attain Keval Jnān and Tirthankar‑pad.

Sect note:

• This point (Bharat and Bahubali as future Tirthankars) is clearly emphasized in Digambar texts and pravachans.
• Śvetāmbars generally respect Bharat and Bahubali as great souls, but do not give as much detailed, fixed teaching about their future Tirthankar status as Digambars do.

So, the two brothers you are asking about are Bharat and Bahubali.