The reason ------------------------- is that he is unable to

The reason _________________________ is that he is unable to operate the machine.(hire)
我弟弟没有被雇用的原因是他不会操作那台机器.答案是why my brother is not hired,想问可不可以用现在完成时态啊?就是why my brother hasn't been hired这样写,为什么可以或者为什么不可以呢?