No, Andacava, Bosnia is not part of the Schengen countries and as such a Schengen visa is not required to go to the country. However a person with a multiple entry Schengen visa is only allowed for a maximum period of 7 days in their country. No more. According to the Bosnia Foreign Affairs Ministry website, Ghanaians require a Bosnian visa before they are allowed entry into Bosnia. And the closest Bosnia consulate is in Cairo,Egypt. So please let the person visit their Foreign Affairs ministry in the country to find out how they can get you to come visit and have an extended stay in the country.
I spoke about the Schengen visa when you just mentioned the EU without mentioning the country. Sorry to have confused you. Let me know if I'm clear enough.
However I will be checking on it so if I do get any new info I will send the details to your mail. So please ensure that it is the correct one.