First I have this poster, you can put somewhere or in your local highschool.
You can go to the facility and hold a poster up with an encoraging message while you are standing on public road.
Next there is allways the the possibilty to enter a forum nationwide and write your story and how you miss friends. Mention how you have to wait until they are 18 and then have to locate them in the nearest shelther.
You can write a wish-well add in the local newspaper in the area where your friend is being imprisoned.
But:
There is no need to harass a ordinary staffmember, who has taken the job because they are young and naive in an effort to save the world or had to take the job because they live in a remote area where the facility is the only job-option.