While that is true, the OP has not stated staying was his intention when he entered. A change of intention after entry is not visa fraud. Intent on entry is the key either way. If he changed his mind after entry, adjusting status is an option, but a person from Ghana who was able to obtain a visitor visa for the USA, presumably had strong ties, likely including a well paying job.
The problems associated with adjusting status are that if he leaves before obtaining advance parole, he won't get back in, and second, it will take that same six or more months before obtaining authorization to work in the USA. All that time without a job, and/or the ability to travel internationally, often become deal killers.