Hi jubilee196,
Thank you for posting in Apple Support Communities! From our understanding, when attempting to FaceTime a specific contact, the call is failing, is that right? Are either of you able to FaceTime any other contact? You also mentioned that your device will not let you update to the latest iOS, is that also correct? It's possible that the device not being up to date is the cause of this. Let's work on getting it updated.
You mentioned turning off Wi-Fi, you'll want to be connect to a strong Wi-Fi network in order to update. After connecting to Wi-Fi, use the steps here: Update your iPhone, iPad, or iPod touch. If you run into an issue updating, you can follow the steps in this article to troubleshoot: If your iPhone, iPad or iPod touch won’t update.
If this continues after updating, you can follow the steps here to troubleshoot: If you can't make a FaceTime call on your iPhone, iPad, or iPod touch.
Also, you confirm that neither one of you accidentally blocked the other's contact information: Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch.
Hope that helps!
