If someone suffers from a psychotic episode, and you accuse him of something he does during that psychotic episode without mentioning anything about the fact that he was suffering from a psychotic episode, then that is unambiguously a lie by omission.

People who suffer from psychosis do not behave in a reasonable manner. A psychosis is a medical emergency. It's like complaining that someone caused a traffic accident without mentioning they had a heart attack.

(Disclaimer: I have never heard of deBoer before, and for the sake of discusion I am going to assume he did in fact suffer from a psychotic episode)