In US, getting a 助理教授 (not助教) is the hardest
part. and most people get 终身副教授 after a few years.
中国科学院院士's level is the same as that of postdocs
in US or most of them are even less. He is more than enough to be a 中国科学院候选院士.
I do not think that 中国科学院院长 is able to get a 助理教授 position in a US university.