The board said "he was not consistently candid in his communications with the board". That could mean little more than he once neglected to inform the board of something the board felt was important, which is almost certainly true. It's almost certainly true for any CEO; if you take it literally and don't read between the lines it's a very mellow accusation.

On HN and twitter people read that line and interpreted it to mean "he's a liar" or even "he raped his sister", but the board didn't actually say those things. He could try suing the board but I think he'd lose.