Working in malaysia under tourist visa?

i have a friend who refer ed my brother to a malaysian agent.but my brother left philippines under tourist visa for 1 month..the agent said that he will process his working visa in malaysia.he start working as a waiter somewhere in penang.my brother's tourist visa will expire on sept. 29 and he still do'nt have working permit.the agent said that even if the tourist visa expires,there is no problem because his working visa is under processing.is it possible that he can stay in malaysia even if the tourist visa expires?how long will it takes to process the working visa?what if the immigration caught him after his tourist visa expires,will the immigration detained him?does the immigration beat prisoners?my brother do'nt know if he just have to go home before his tourist visa expires or wait until the working visa release?