To answer your first question, you have to understand the power structure in these gulf states, one thing that super obvious is that the ruling family in Qatar (Al Thani) with the Emir at its helm hold total power in Qatar, Jassim is a distant cousin of the Emir and a member of the ruling family, and his father was a powerful figure during the reign of the former Emir. Jassim is also known to have grown up with the current Emir (Tamim) and they went to boarding school in the UK, not necessarily in the same time/class/cohort, but they are only 2 years apart in age.
The Emir of Qatar has basically a final say in all matters, including who holds positions of power in public and private sector (most of major corporations are either wholly owned by the state or majority owned by the state or it's investment arm QIA), Jassim is a chairman of one of the biggest banks in Qatar, he is appointed there with the Emir's blessings, so in terms of links/connections to the royal family, he is very much connected.
As for if the bid is a state bid with Jassim as the face/figurehead, that can be debated, but in my humble view, it is most likely something that Jassim most likely wants to do on his own, but it requires at the very least the Emir's implied approval/tacit approval, if the Emir objects to it, Jassim would defer to his ruler, even if Jassim was using his own money/family's money.