Why is my husband's iPhone not recognizing the invitations I am sending to him?

[iMore Question]

I have sent repeated appointments to my husband's iPhone from my iPhone and they are not showing/adding to his calendar even though I can see that he accepted the appointment in my calendar invox.

 

[Just_Me_D]

Does he have the calendar checked to be displayed on his device? In other words, if you initiate the native Calendar app (I assume that's what the both of you are using since you didn't state otherwise), then tap on "Calendars" at the bottom of the screen, you will see a listing of your calendars. If a calendar does not have a checkmark next to it, it will not be displayed.