Henry knew that before he could take any sort of action, any sort of attack against Bloodmoon, he had to go and speak to his father, his Alpha. Anything else would be tantamount to treason. Though he might not kill him for it, his father would not look on his son kindly for his actions.
Henry also knew that his father wouldn't respond well to a phone call, so he had to make the journey out to meet him.
He was supposed to be staying away from his father, especially in the condition that he was in now. But Henry trusted that his father would see that this was an emergency and would forgive the oversight in protocol meant to protect their pack.
It was only for the future of Wolfsbane that Henry's father, Henry Sr., kept his son at a distance from him. He needed to be sure that if he died, his son would be there to take over in his stead. He needed to be sure that they would have an Alpha to lead and care for them, no matter what happened to him.