I am happy to assist you.
An adoption of an 18 year old is very straight forward and generally not very costly. It would terminate the biological parent's rights and make you the child's legal father.
The process, generally speaking, is to file a petition to terminate the biological f parental rights and to permit an adoption. The process is simpler if the biological father consents as well. However if consent is not possible, the court may waive the biological father's consent based upon the majority of the child (18).
Generally speaking, an adult adoption is a fairly streamlined process.
First you complete a petition and file it with the court. After you file the petition, the court may do a home study of your family, however this step may be waived by the court. Finally there will be a hearing to finalize the adoption.
The forms and procedures will need to be followed completely,
If you cannot retain an attorney then you can copy the forms at your local law library or buy the forms on line complete with instructions. I found a site with state specific forms that you can use. Here is the link for Rapid Law: http://www.rapidlaw.net/adoption.html
Best of luck with your family.
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