The affix vyat also comes in the sense of descendant after the word bhrātṛ,
By the force of the word च in the sutra, we get the affix छ as well.
This debars अण् ॥ Thus भ्रातृव्यः or भ्रात्रीयः 'the brother's son'. The त् of व्यत् the regulates the accent, making it svarita.,