(a) mr-hank did or said something sexually inappropriate. (He lost ground by admitting some degree of guilt on HN. Otherwise, it'd all be hearsay and he could say he was just talking about a literal dongle.)
(b) mr-hank's conduct was so bad that there was no choice other than to fire him: "having to let this employee go". It wasn't we decided to fire him. It was we had to fire him. Important distinction, and quite likely, technically false. They probably fired him to save face, not because of an objective violation of any law or ethical principle that left them no other option.
It's not a clear-cut case, and it's less so in the light of his HN admission, but he can certainly argue that the press release (a) misrepresents his behavior, (b) in a way that will damage his reputation and future employability.
He has a lot of options here. He may settle for an amazing reference and introductions to investors. Or he might get a six-figure sum out of it. Or he might walk away. Depends what he wants.
PlayHaven fucked up big time. These companies (especially PlayHaven; SendGrid has more of a case) should be more embarrassed than the people involved.