Did you also notice that he was exercising his options at a lower price than what he is selling off? The stock just split ... He's got double the shares, and options to buy more at a lower cost ( almost half the price) than the current value of the stock even after the split.... Sounds to me like he is wisely putting a little cash in his pocket , but I could be wrong. I'm just a novice.
Read the information that's available on the charts and maybe you will come to a different conclusion.
Executives are not allowed to sell on the open market anytime they feel like it. They follow a predetermined schedule when selling shares to the market. This is filed in advance well ahead of the current days share price/value.
This "selling" can be thought of as "paycheck" as stock in the company provides the bulk of their executive compensation.
This is market 101. Buy a clue or put your money back under your mattress.