Once your son is 18, he will need a photo ID. Here is a list of what is acceptable taken from the TSA website:
* U.S. passport
* U.S. passport card
* DHS "Trusted Traveler" cards (NEXUS, SENTRI, FAST)
* U.S. Military ID
* Permanent Resident Card
* Border Crossing Card
* DHS-designated enhanced driver's license
* Drivers Licenses or other state photo identity cards issued by Department of Motor Vehicles (or equivalent) that meets REAL ID benchmarks (All states are currently in compliance)
* A Native American Tribal Photo ID
* An airline or airport-issued ID (if issued under a TSA-approved security plan)
* A Registered Traveler Card (that contains the following: Name; Date of Birth; Gender; Expiration date; and a Tamper-resistant feature)
There are also guidelines about telling the person doing the screening that
your child is disabled, etc. Hope this helps.