Though Liam told Oliver he believed him, he knew that few outside their family would share the same sentiment. Outside the walls of the hospital, people would likely laugh at his brother, a risk Liam wasn’t willing to take. He loved Oliver too much.
So, Liam and his parents promised to support Oliver and spread his message, but only once he had fully recovered. If he truly intended to save the United States, he would need to be in better shape. Seeing no other option, Oliver agreed.