Sole custody was likely granted so aunt and uncle can make decisions regarding things like the child's health given the parents are not in the country. Sounds like the parents had the child in the US and then had to return to Pakistan. Whether they had legal status at the time who knows. Wanting the best for their child they sent they son to stay with their brother/sister for a western education. That is exactly what an adoption of convenience is. Although the child has been in your care for 5 years he was in the care of his parents for 11 years. I would imagine he still has regular communication with them and refers to them as mom and dad. That's not a case for H&C either. This is a family decision not an adoption or an H&C case. If I had to guess the child likely visits this parents annually (or at least every couple of years) in Pakistan. He could return to Pakistan, if necessary, to continue his schooling. Unfortunately if he goes to university this will get even more expensive. Would likely have been better to save money for his university education not high school. Sure this is the case of a loving aunt and uncle but doesn't change the facts.