As reported in the Taiwan news, his brothers called a special board meeting while he was out flying a trip, fired him as CEO, had him removed as Captain of the return leg, and made him deadhead home.
Technically the will was fulfilled, as he was allowed to sit as Evergreen Group Chairman for two days. Then they actually abolished the position, so that even if he prevailed in court on the will, there would no longer be any Group Chairman post to assume. That's where the case would really get nebulous.
The new EVA CEO was the previous one before Mr. Chang assumed the role. Hopefully this doesn't adversely affect their overall quality as an airline.