Not sure if you are really asking a question or making a statement:
If a question ie you are not sure whether a person is a man or not, you can say, is he a man? I don't know if that person (you should not use he/she here as you do not know whether it is a he/she) is a man or not.
If a statement ie you want to say that person is very shy/timid, you can say:
Be a man, don't cry over spill milk
Peter is a coward, he should have stood up for his friend, is he a man??
我諗係I don't know he is a man or not(第一個果個黎= =')最準呀,因為呢,male係男性= =(d人咁都答得出嫁),都唔係男人!~另一個係咩野knoe,果個直情係錯tim la!字都串錯!你再唔知既你咪去yahoo打reporting question(我諗係reporting question黎= =),你最好就係問老師!!