An Executive Committee cannot vote to overturn any decision of the Owners Corporation taken at an AGM so this is not an option.
You need to explain how this lot owner bought 2% of the unit entitlement as these aren’t something you can buy and sell to the best of my knowledge.
Did he buy 2% of the land of the older owner if so you could look at whether this was done legally and were all the dots and t’s were crossed because if it wasn’t done correctly he would only have 24% and not enough to stop you proceeding.