I don't know, but Chris L was always a C++ guy, he never really understood Objective-C in my opinion, which is why Swift ended up the way it did. I doubt he ever used it very much, or had a deep understanding of it.
I’m pretty sure Chris Lattner has a good grasp of Obj-C, after all they had to design Swift in a way it could easily interface with Obj-C. While Swift went through some versions to become stable, they were always transparent on the roadmap and had a very open attitude towards community proposals.
Looking back I think it was a very well executed transition and would consider it a success in every way.