We have discussed this question and possible answer more than once in this thread already..
But I'll try and answer for the last time and go into a little more detail: Many people close to the situation believe, as Michael was being controled and manipulated by his handlers, he may also have been or felt "threatened" by them in some capacity? We already know from his owm words, he feared Tohme. We already know Tohme refused to leave his employment.
Could he have been afraid to let on, on the day of the family dinner/party about what was going on?
Or was he in denial about something?
He is Dead now from what looks to be a very mysterious death.
Think about your answer very cautiously...