It seems strange that your friend's parents would include "no confirmation" in their divorce proceedings. Not knowing all the circumstances, I am assuming your friend either has little spiritual support or encouragement from his parents and possibly even strong pressure to not be a Lutheran Christian. You are going to have to fill that void. Pray for your friend. Discuss spiritual matters with your friend and encourage him/her to read the Bible. Encourage your friend through your words and actions, showing him/her that being a Lutheran Christian changes your life now and forever.

In answer to your question, yes. Once a child reaches a certain age, I believe it is either 18 or 19, legally they are considered an adult. If your friend is still interested in confirmation at that point, they would be free to take classes even if mom and dad don't want them to. However, if your friend is interested now, I would encourage your friend to talk to mom and dad to see if they would be willing to let them go through confirmation now instead of waiting. If they still refuse, then do whatever you can to encourage your friend to remain connected to God's Word. Invite your friend to come to church, Bible study, and youth group with you. If his/her parents won't allow it, then continue to do the things you are currently doing which I mentioned earlier in this post. It's wonderful that you care about your friend's spiritual health. God's blessings on the help and encouragement you give!