My son's exwife moved to Texas 4 yrs ago with her new husband and my 6 yr old granddaughter, without telling my son about it. He pays child support but doesn't get to see his daughter because of his exwife being difficult. He has to pay airfare so we can see her at all, which is a few days once or twice a year, even though the court ordered every other weekend and 2 weeks in summer. The daughter is 10 yrs old now and wants to live with her father. What can he do about visitation and custody? My son lives in Georgia where the divorce was obtained.