My fiance & son are americans in ghana, and I need help to get them back home, how can you help?

My fiance and her son have been living in ghana for three years taking care of her mother and I need help to get them back home a.s.a.p. because we are getting married! they are doing the exit paperwork to leave, but I don't have the airfare to bring them home to me in Las Cruces, NM, ?will they usa government help with the airfare to bring them home if I promise to pay back the governnent a little bit at a time?