We know he wanted Manziel and wanted to pick him. We know he wanted Dez Bryant on this team now.
Did either of those things happen? if you are smart enough to see that neither of those things panned out, why didn't they?
Simple, he decided to listen to the people he pays to give him advice.
When you have a business solely owned by one individual, that individual has the power and authority to do whatever he wants at any time and NO ONE can stop him (aside from extreme situations where the league could intervene).
Its Jeris team, its his business, this is not a democracy, its not a corporation, its a dictatorship and in your examples, jeri merely chose to go along with the consensus presented to him but could have forced the team to draft Manzeil if he had wanted to.
Why is this so difficult for you to comprehend?
I will say this, there is a greater than 0% chance that jeri has created a living trust to avoid massive tax consequences to his business and family following his death. Perhaps there is something in that document that has immediately limited Jeri's power within the organization but given this is a document that would be created at his behest, I seriously doubt he would do anything to undermine his power and authority given his obvious need for it and how he has proclaimed since the day he bought the team that he would be in charge of everything from jocks to socks and the final decision on all matters rests upon him and him alone.
Ex: Just because he gives his secretary control of a petty cash account of $500 doesn't mean she has neutered his control over that fund, he can jerk it back at any time he likes.