Storage of encryption key on A6100 dongle

Hello - I know this is a silly question however I am looking to see if anyone has any documentation....

For the A6100 wireless dongle, I have a customer that is insistent that if the dongle gets stolen, a malicious actor can hack into and discover the password for their WAP2 SSID.  This connection is using CCMP and the encryption key is being stored on the PC itself, however I am looking for any supporting documentation that no confidential information is ever stored on the dongle itself (I believe at the data link layer of the OSI).  Is anyone aware of any supporting documentation that I could provide the customer to ease their belief?