Facetime: AutoAcceptInvitesFrom not working

Since my update to the latest high sierra (10.13.3) on a MacBookPro, the AutoAcceptInvitesFrom-Function in Facetime (autoaccept facetime calls) no longer works.

Does anyone has a fix?

I exactly need this function for my mother, who has dementia and is no longer able to press the accept button - so please just answer when you have a fix for exactly this problem.

the parameters are set like this:

<key>AutoAcceptInvites</key>

<true/>

<key>AutoAcceptInvitesFrom</key>

<array>

<string>myadress@foobar.ch</string>

</array>

I appreciate any help

thanks