He might be able to learn something about his family through DNA testing.

I found this information by using ChatGPT:

"In Guadalajara, Mexico, several adoption services can help guide prospective parents through the adoption process:

1. DIF (Desarrollo Integral de la Familia): This is Mexico’s national agency for family welfare, responsible for handling the majority of adoptions in the country. The National and State DIF offices facilitate adoptions of Mexican children and ensure all legal requirements are met. Prospective adoptive parents must apply through DIF, which will guide them through the local regulations and procedures, often requiring a stay in the country during certain phases of the adoption.
2. Children’s House International: An international adoption agency that works closely with Mexican authorities, including DIF. They provide services such as home studies and support for U.S.-based adoptive parents. The process involves several steps, including dossier preparation, court visits, and multiple trips to Mexico, as adoption laws in Mexico generally require both parents’ presence for certain steps.
3. Open Door Adoption Agency: Open Door facilitates adoptions of children in Mexico, typically those older than nine, sibling groups, or children with special needs. They help applicants meet both U.S. and Mexican adoption requirements, manage dossier submission, and assist with the required in-country visits. Open Door works primarily with Christian families and helps with the U.S. immigration process post-adoption.
4. Hands Across the Water (HATW): This agency supports international adoptions from Mexico, focusing on helping parents understand the cultural aspects and legal procedures. HATW coordinates with Mexican authorities and provides support for required documentation and travel arrangements. They also manage post-adoption follow-up to ensure the child’s integration and well-being in their new home.

For U.S. citizens, it’s essential to follow guidelines outlined by both Mexican and U.S. authorities. The U.S. Embassy in Mexico provides resources for American families, including information on required documents, travel, and visa processing for adopted children.

These agencies help manage the complexities of international adoption from Mexico, which can take several months due to legal, cultural, and procedural requirements. For more assistance, you can contact each organization directly to understand specific requirements and fees."

Hopefully this will help you.