Hey, welcome back
My teen developed depression (and anxiety), too.
He seems to be through the depression but not the anxiety.
What kind of relationship does your teen have with dad?
I found myself dancing around topics with my kid until he started to make emphatic statements. We don't linger in the deep end but we do hop in and out. I sort of farmed things out to the therapist but notice that the best stuff seems to happen when it's the three of us -- me, S19, and his shrink. I don't know what we're really going for but I can tell when it's happening, if that makes sense. I miss the in-person sessions because pauses were more meaningful or seemed easier to read.
What kind of custody/visitation are you working with?