There's a random event with a chance to trigger when you return to the camp after Scar wakes up. The conversation will be available then.
Spoiler (How to get the event)
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
I don't know if you got it yet, but I'll still comment if someone else needs help. I got it, like, 3 days after Scar woke up. I think the best way to get it is to stay in the forest with the goblins for 2-3 days then return to camp. I suggest collecting berries and making health potions if you're thinking of fighting them instead of escaping the battle. It was also night (0:00+) for me if that helps.