I like the way Lao Li takes care of Da Qing. And I really like that scene in episode 13 when they calm Da Qing and Lao Li pets him as if one would pet a cat. And I love angst, so I found his death scene and Da Qing's grief very affecting.

Does Lao Li live inside the SID building?

I never thought that he lived at SID. I thought everybody but Wang Zheng lived somewhere else. But now that you mentioned it - I think it is possible that he does live inside the SID building. It does seem like he's almost always there.