The OP lives in Wisconsin. Wisconsin allows under Wis. stat. 895.035 for the parents of minors to be sued for certain torts of the minor but caps damages at $2,500 per wrongful act. The same section also provides that a parent may be ordered to pay restitution for certain criminal acts of minor children if the minor child does not or it appears that the minor child will not pay them. So in that instance, assuming that the theft is determined to fall under the terms of the statute the parent may be held civilly responsible and subject to covering the cost of the criminal penalty, although not to serve any prison time.
IANAL and YMMV by jurisdiction.
