I think they meant that he gets the 37% of shares that his grandfather owns of the whole company. So his grandfather owned 37% of the company as a whole. ML got 100% of the the grandpa's 37% making ML a majority owner.
Companies like that have a shareholders board where each member owns a certain percent of the entire company.
I don't know. Maybe its mistranslated but it says "30% of equity in his hand" this sounds to me as out of stocks that he owns (only grandpa's share) 30% of that go to his grandson.
It could be either. I just know from other manga a d tv shows that shareholders boards is how they do it in big companies
if MC inherits 37% of his grandpa shares in company and uncles get nothing, who get the other 63%?