Talking to Humans is Too Difficult

So I recently had a family member pass away and was encouraged to call their partner and apologize for hearing about their death. I was about to call but then started thinking more about what this conversation was supposed to consist of.

How am I supposed to greet them? How am I supposed to end the call? What should I avoid saying? How do I talk to people???

Humans are too complex for me to understand. I’ll always say the wrong thing even if it’s right to me. I just wish I could talk to people.

Now I can’t get myself to call them because I’m worried I will do it wrong. I feel like if I call them and say the wrong things they will die too. Is this normal? Am I just overthinking?