YG is facing possible prison time for threatening to kill a trainee (among other things), and as he is the majority shareholder if that happens, it's going to have a negative effect on the company and the share price.
From my 10 minutes of googling it seems like the company could be wound up without his permission if all other shareholders agreed, but his brother also owns shares. He's also the current CEO.
YG once said he owes everything he has to Seo Taiji, Teddy Park, and G-Dragon. So maybe he might offer to sell his shares to GD or Teddy to secure the company's future?