Thought I read something this morning somewhere (can't seem to find it now) that they were going to coach him on what to say, implying they were just going to pull a Whoopi on him.
Yep, they pulled a Whoopi - he's back: https://www.msn.com/en-us/news/politics/disney-explains-jimmy-kimmel-decision-as-company-announces-show-s-return-day-after-charlie-kirk-memorial-live-updates/