"confused ... UCS-2 and ... UTF-16" - You are quite right, he is clear on the difference. It's presumably possible to apply the same trick to UTF-16 as was applied to UCS-2, to expand further, but this is ad-hoc and not built in.

"supports 16-bit char width" - I mean the compiler has CHAR_BIT == 16; this is independent of the character encoding of the source.