Activate FaceTime on iPhone 6 remotely for an elderly person

My mom is 85 and I want to FaceTime with her, but she is totally lost with the phone I sent her. With Covid crisis a store visit is not a good idea, nor sending a friend to help her. She can answer a call, but lost past that. I tried to activate online with her Apple ID. The phone number and IMEI are registered. On my end I get a ? in the video box and it doesn't go through on her end.

Can I activate FaceTime with her Apple ID online? I registered my iPad to her Apple ID account to test, and the iPad rings. Unfortunately I'm a thousand miles away from her. Installing another calling app is impossible for her.

Is there anything I can do remotely for FaceTime?

Thanks from a desperate daughter :-)