In my game I only heard him shout "get up, godsdamn you!" even at max approval.
Nope, I still can't get him to say those lines, sigh. I'll edit if I notice anything new, but so far he never makes a comment when he helps my character in or out of combat. I also have no idea how I'd trigger the sneaking ones. The point-and-click voice lines are a little tricky too because even if I set the dialogue frequency to "Always" in the settings, it doesn't always trigger a voice line when I click.
As a sidenote - I heard Minthy say "Your flesh will heal!" when she used Lay On Hands on my character once, which was cute. Meanwhile, I can't get Astarion to say anything.
Yeah, when Tav/Durge falls unconscious, he still only says "No you can't die, get up damn you!" / "No! My sweet bloodthirsty friend."