An adult cannot be declared as a minor child. You may be able to adopt the adult or you can seek guardianship. If the adult is competent, you may also do Power of Attorney or other estate planning documents to legally assist this person. Speak to a local family law or general practice attorney regarding options.
Kentucky law does not certify specialty of practice in this area. The advice given herein is informational and should not be considered as creating an attorney/client relationship. Michael Bouldin is an independent attorney located in Northern Kentucky. It is strongly recommended to not give any confidential information on any website.
First, an adult cannot be considered a "minor child." If the couple wants to adopt the adult, they should consult a family law attorney and provide him or her with all of the facts. If the adult has parents living, this will be difficult.