You can be adopted as an adult. My partner's Grandma was adopted by her longtime step-father in her 50s in the USA. Japan uses adult adoption to pass family own

You can be adopted as an adult. My partner's Grandma was adopted by her longtime step-father in her 50s in the USA. Japan uses adult adoption to pass family owned businesses to nonbiological successors. Of course the exact rules vary by jurisdiction and country. Here are the rules for California. https://www.courts.ca.gov/documents/BTB_23_1A_35.pdf https://www.courts.ca.gov/documents/BTB_23_1A_35.pdf https://en.wikipedia.org/wiki/Adult_adoption https://en.wikipedia.org/wiki/Adult_adoption