"The thing is I think eventually I should bring up how scared I was when i heard he is gone and nobody knows when he is coming back. And also that they said he might be replaced if he is not back. I have spent some days being seriously worried and restless and all emotional being afraid he would never come back. He needs to know, right?"
Joanna- this is what is important. If you are comfortable with starting with your scared feelings when T was away and how it impacted you, start there. If not, try a lighter topic first. Sometimes it helps me ease into by telling T, I have something I want to talk about, but it's going to take me a while to get there. She can then help me figure out how to best get to talking about a more 'heavy' topic.