Cliff Notes Version:
Bowlen set up a trust in 2002. Although it is still secret, it is believed that this trust would transfer ownership equally to his children when he died.
Bowlen set up a new trust in 2009. This would transfer ownership to three people, two of which were Broncos employees. One of the employees is CEO Joe Ellis.
Bowlen died of Alzheimers.
The three people are trying to get one of Bowlen's daughters to be set up as the sole owner.
The other kids are fighting this.
They say that Bowlen was showing effects of Alzheimers around 2005.
They say that Ellis recognized this and started to influence an incapacitated Bowlen. Ellis fired many employees who were loyal to Bowlen.
They say that the trust are setting up the one daughter as a figurehead so that the trust can remain in power behind the scenes.