Sein is such a bro. Walks in, doesn't even bother for an explanation, and heals Stark. I hope he finds the onee-san he is looking for soon as he deserves it. Wait, I mean his friend...
I wouldn't be surprised, but I don't think it was that explicit. It was basically Sein asking about Gorilla Warrior and then that older warrior basically raising a metaphorical eyebrow in response. Then we moved on.
Given the way that this group of fighters tend to operate with alter-egos, I wouldn't be at all surprised if Gorilla Warrior is living under a different name now, complicating Sein's search.