The translation of the last two setence is interesting.

The English version and the Chinese version say different things. Take a look at this sentence:

"If he wasn't before, Mangini's dead to Belichick now。。。"

According to my understanding, Mangini's dead to Belichick means B breaks off any relationship to M. To B, it is as if M does not exist. The sentence says the following:
1. B was angry with M. It was likely B does not want anything to do with M.
2. After the recent action by M, B is now more angry with M. B definitely does not want anything to do with M.