I am sorry you did not get the support you deserve. Here are some answers for you.
1. You could use a USAA Used Car Loan to buy your friends car. Click here for more information.
2. If approved by USAA, the current "Lien Holder" (i.e. your friends Credit Union) will be paid by USAA.
3. USAA will work with appropriate agencies to have a "new title" created putting your name on the "new title" and putting USAA on the "new title" as the current "Lien Holder".
4. Call 1-800-531-USAA (8722) and speak to one of USAA's Member Service Representatives whom will be happy to assist you.
I hope I have answered some of your questions.
If I understand you correctly, you should be able to use an auto loan. For an in depth answer that is catered to you personally I recommend you call 1-800-531-USAA (8722) (say auto loan to skip the menu) to talk with an auto loan specialist! Thank you!