Simplify the following text for a Grade 9 native English-speaking person.
Original: Roberto de Assis Moreira , commonly known as Assis ( born January 10 , 1971 ) , is a former footballer who is the brother , manager , agent and adviser of Brazilian footballer Ronaldinho .
Simplified: Roberto de Assis Moreira ( born 10 January 1971 ) is a former Brazilian football player .