Why the original owner allowed company to use his own account? By the fact that he handed down password and permissions to the company to operate this account, one could argue that this is not his own account anymore.
However, whoever wins this suit, the right thing to do for LinkedIn would be to just disable/delete the account for misuse. The fact that multiple people inside a company had been sharing the same account, changing person name, picture and position is a bit fishy, and potentially a scam against other linkedin users. I wouldn't be happy to connect to "John D" and write recommendation to him, only to find out that few weeks later this is some "Alex F" I don't know.