How to have a specific contact make a ring sound even in silent mode

This is an old question but I stumbled on it when trying to find an answer for my iPhone 8. There is now a real solution to this problem— edit the contact and turn “Emergency Bypass On”. The text says it overrides Do Not Disturb, but I tested it and it overrides the silent switch too!

This is an old post, but I came across it today looking for the same thing. For an iPhone 5c, running iOS 10.3.3, I found that going to Contacts' > 'NameOfContactYouWant > Edit > Ringtone (or Text Tone) > Emergency Bypass On will allow calls/texts to go through when the phone is otherwise silent.

That's one of the benefits of the "Do not disturb" function in iOS 6:

• assign all contacts which can reach you even when you don't want to be disturbed int a contact group via iCloud
• activate "Do not disturb" in Settings and configure the Notifications settings to still allow calls from the contact group you created. You can also schedule a time range when you want Do Not Disturb to automatically activate.
• silence switch will still work as intended (silencing the phone)

One (painful) workaround is to give She Who Must Be Obayed access to your Apple ID so she can use Find iPhone to "Play Sound" if you don't answer your phone. AFAIK that is the only Apple-approved way to play a sound on an iPhone while the phone is muted.

Don't use the mute button. Instead, use the Do Not Disturb manual function in settings and select "Allow calls from Favorites". Open a contact and select the star from the bottom right to make it a favorite.