You may already have had a power of attorney drafted that lets you act on behalf of elderly parents. And it’s possible you have estate planning documents dealing with the possibility that you or your spouse could become incapacitated. But what about your college-age children?

That’s not as crazy as it may sound. Once a child becomes an adult under state law, you may have to rely on the following documents to enable you to make important medical and financial decisions for your son or daughter.

Health care proxy. Under the landmark Health Insurance Portability and Accountability Act (HIPAA), parents may not have access to their children’s medical records even in the case of a serious accident or illness. HIPAA generally prohibits medical providers from revealing confidential information about their patients. However, a health care proxy can give parents the access they need. This document allows a child to designate someone—usually a parent—to make health care decisions on the child’s behalf in case of physical or mental incapacitation. Such decisions may include approving treatment options and medications. If you establish a health care proxy with your child, be sure to provide copies to the college health services and to the child’s primary physician.

Durable power of attorney. This document ensures ongoing management of the financial affairs of a child who’s unable to take care of those matters. Typically, such a document designates a parent as “attorney-in-fact,” so that if a child becomes incapacitated, the parent can step right in. For example, you might need to take action relating to investments, bank and credit card accounts, leases, student loans, tax filings, and the like. A durable power of attorney could also let you take care of things stateside while your child goes abroad for education. Be sure to give copies to your child’s school, the financial aid office, and other relevant parties.

Wills and trusts. Though many college-age children may have no need for a will, it’s a sensible precaution for those with substantial assets. A will and perhaps a trust can help avoid having assets revert to the parents if a child should die—a transfer that could complicate the parents’ estate plans. Trusts can be efficient tools for sending wealth directly to a sibling or to another relative, and assets held in trust are also exempt from probate. Finally, a will and trusts could be structured to minimize potential estate taxes.

If a child becomes incapacitated without a health care proxy or durable power of attorney in place, the family may be forced to pursue a guardianship or conservatorship arrangement. That can be costly and time-consuming—and easily avoided by establishing these few essential estate planning documents.