People do say 'what is he', and it doesn't sound wrong to a native speaker providing it is within context.
If you are asked 'what are you?' without any context then the response would be one of confusion and maybe a person? a human?
Having said that- just because people say it, doesn't make it right.
It is a very lazy way of speaking English, and would never be used in formal situations.
You should be asking, what job do you have? / what is your job? or most commonly 'what do you do for a living? '.