It doesn't necssarily have anything to do with funding. If the Qataris want to take the company private, they need to buy out the other share holders. While Ratcliffe doesn't seem to intend to take the company private, so all he needs is a controlling share.
There are a number of benefits and disasvantages to going private. However, the most crucial element is usually that a listed company has much stricter rules on transparency, accountability to shareholders and reporting requirements than a private company. Which traditionally is beneficial for sport washing projects, not saying this is definitely the case here, but it's a point to keep in mind. When you don't plan to take the company private, it does not make sense to buy anything more than a controlling share, because taking a company private requires you to buy out the other share holders at a premium. At that point you are basically throwing money out the window.