A. It seems to be missing a few conjunctions here and there.
“departure seemed so certain (FOR) this week..
B. The heavy use of the same Second-Person pronoun “He” is confusing.
“HIS boss’s chief of staff told colleagues that HE had been..
C. The whole mess equals what my English teacher would have called a Run-On sentence. That happens when the writer tries to make the Topic sentence do too many things.
I recognize Run-On sentences because I often make that mistake myself. I forget to take a breath. Front loaded sentences remain out of balance.
Nice summary your Leeness. C. is the best point.