Me and my wife are both united states citizens and we want to adopt our 15 year old nephew he came into the country with his parents from mexico illegally can we adopt him and his parents are willing to sign him over to us.

The answers is you can if he is in mexico. You can't adopt him here because he is not a citizen of the U.S.

He can return to Mexico and then you would follow Mexican law for an adoption to take place.