A vape was confiscated from a minor. It was not his. Can a parent/guardian sign for it to get it? Is there anyway they can get it?

Not likely.

If it's less than a hundred bucks to replace, it's probably not worth the effort.

In Europe, no. If you're old enough to have such a thing, most European laws say, it is your duty to take care that it does not get into the hands of minors, even if they are "just holding it".

The police, however, does not gain possession either, because that would be theft by the state. But the oly person who can effectively reclaim it is the 18year old, as he's the owner, no other person on his behalf.

And mind: If you try as a parent/guardian you can make things even worse, because that proves that the 18yr old isn't able to handle his own things.

I've never heard of a law covering this, sounds more like a department policy. You need to call the department who is holding it to find out what their policy is.

There is no federal law on this, so without naming your location....no one can tell you if that is correct or not.