The driver, Dharmendra, had gone to attend Durga Puja in Sikandarpur town late last night when a brawl broke out over a dispute between children, Deputy Superintendent of Police Anshuman Misra said.
Dharmendra was attacked with sticks.
Later, on hearing the news, the brother of the minister, Ram Bachan Yadav, reached the spot where he was also beaten up, the police officer said.
Both were rushed to Community Health Centre (CHC) for treatment from where they were discharged today.