Suppose a person has accepted a job offer thinking that the work would be closely related to what he wanted to do. Instead it is a dull boring job. If he gets another job offer in a field that is closely related to his background, does it look bad for him to quit his current job?
You have the same right to declare that a position is not a good fit for you as your employer has to declare that you are not a good fit for the position. Having said that, it makes no sense to mention in your resume a position that you held for a month, unless you did something spectacularly good there.
Having said that, keep track of that position because you most probably would have to mention it if you were applying for a security clearance.
Yes it does.
That is not to say that he should not do it anyway just that if he lists the position on his resume the short tenure is going to draw attention that will need to be explained.
The reason is companies are looking for people who are likely to stick around. It is expensive to hire and more expensive to train someone. If you have a history of short term jobs it is more of a concern than a single short term job, but that single short term job will draw attention.
That said we do not live in a vacuum and if your friend is working for a company that is known for high turnover, there is a reasonble chance that someone making a hiring decision is aware of that and it will mitigate the issue.
It will make you look like a "job hopper" to some people if you list it on your resume. Consider how large of an employment gap will appear on your resume if you leave it out. A short stay at just this one job is not exactly a trend, so if you have several other jobs that you didn't stay long, this could make it look worse.
Early in someone's career, I would give some consideration to someone who took a job that didn't work out. You could discuss this in a cover letter. It's a sign of being up front and honest. People always ask in interviews to get some anecdotal information on how you handle problems and what are your areas of weakness. You know it can look bad, but indicate you've learned from the mistake and how you and the former company will be better off in the long run. Basically, you now know what you want in a job.
Do you really want to work for people who are going to hold this against you without considering your other strengths?