How to share location with husband

We recently purchased a floodlight cam and I set it all up in my account and shared with my husband although at the time he did not have an account and therefore did nothing. Today I have created an account for him and resent the request but it did not work. I have read in the forum that it is not currently possible to share a floodlight device and so I was wondering - how can I share the location? I have tried to go into the location and add his email address but the "Send Invite" button is permanently greyed out and it will therefore not let me send it. I want to make sure that the Arm/Disarm messages take into account his presence as well as my own.