Not selling the at the price he offered would have been massively violating their fiduciary duty. Twitter stock would probably be worth like $20-30 given the current market versus the $54 offered.
"A Saudi prince who is among Twitter’s major shareholders scoffed at Musk’s offer in a Thursday tweet. Al Waleed bin Talal said he would reject Musk’s overtures because he didn’t believe $43 billion “comes close to the intrinsic value of Twitter, given its growth prospects."
