Here are some troubleshooting tips for a Contact that is not showing the FaceTime icon:
If you can't place a FaceTime call to a particular contact, try the following:
- Verify that you have the correct phone number or email address.
- Use the correct method of contacting the person. If you are calling:
- An iPhone 4 user: Use the phone number
- An iPad, iPod touch, or FaceTime for Mac user: Use the email address
- Check that each person has an active Wi-Fi connection.
- When calling someone using their email address, they must verify that email address for use with FaceTime and be signed in to their Apple ID account. They can verify they are signed in using:
- iOS: Settings > FaceTime
- FaceTime for Mac: FaceTime > Preferences
- Note: If verification is pending, follow the instructions in the email that was sent to that email address to complete verification.
For additional details on troubleshooting FaceTime on iOS devices, see this article.
Since 2 of your contacts are working with FaceTime, then the issue with the third one is probably one of the things listed above.
Hope this helps!