From the article in the OP:
It is possible that the board of directors could vote to allow Trump to sell shares earlier than that. And that board could be stocked with people close to Trump, including his son Donald Trump Jr., former wrestling company executive Linda McMahon, and Trump’s former trade representative Robert Lighthizer, according to a list of planned nominees.
If the board signed off on lifting the share lock-up period, that could quickly free up a large source of cash for Trump, who is the presumptive Republican presidential nominee this year.
Gotta pay those legal bills.