I think the opening up of shareholder lawsuit would only be if he cashed out and left QMC prior to the original terms and option vesting period. If QMC weren't sold and CL stuck around for 3 years, there's no shareholder concern.
In my opinion, the immediate vesting only benefits him if he wants to leave within 2 years or they sell out.
If he was just hoping to sell some shares after revenue, they could have restructured it with only a portion of the shares being immediately vested, i.e. 2.5 million vested now and another 2.5 each year over the original 3 year period.