A judge on Wednesday temporarily froze the assets of Bernard Madoff's brother after he was accused in a lawsuit of losing nearly a half million dollars in a trust he administered. The lawsuit in Nassau County court claims Peter B. Madoff took $478,000 that belonged to Andrew Ross Samuels, 22, and invested it in his brother's Ponzi scheme that fleeced investors of billions of dollars. Samuels, a Brooklyn law student from Long Island, received the money from his grandfather, Martin J. Joel, who had placed it in the trust in 1997 to help pay for the young man's education. It was supposed to be his inheritance. Both Joel and Peter Madoff administered the trust, the lawsuit said. But after Joel died in 2003, Peter Madoff became the sole trustee and invested Samuels' money in his brother's firm, Bernard L. Madoff Investment Securities, the lawsuit said.