I have a friend who's thinking about running away to another state. What can the law do if he's caught ?

How old is this friend of yours? Why is he thinking of running? Who is he running from? His parents? His parents would report this as a runaway or missing teen and the search would be on. When found, he would be in police custody and sent back to his parents.

What happens after that - counseling is recommended for the family - individual and joint. They have to find out why he felt the way he did and then how to address his problems. Hopefully to the satisfaction of all and that he does not feel the need to run away again. If the running away is persistent - he could find himself at a place like a Youth Center or residential place for teens.

[to ~Dr. Seuss] what if the runaway stays with a friend who's family supports them and they don't want to go home??