Adults may be adopted with consent.Most Relevant Texas Statute:Chapter 162, Subchapter F. Adoption of an Adult
§ 162.504162.501. Adoption of Adult
The court may grant the petition of an adult residing in this state to adopt another adult according to this subchapter.162.503. Requirements of Petition
(b) If the petitioner is married, both spouses must join in the petition for adoption.162.504. Consent
A court may not grant an adoption unless the adult consents in writing to be adopted by the petitioner.