Joshua takes a vacation. Or rather Chase goes on a cleanse bc he his body became dependent on drugs. The attending doctor told Joshua and Chase that it's not good for Joshua to be around Chase bc Joshua is affecting Chase's pheromones. So Joshua was advised to stay away while Chase recovers. After some long convincing, Joshua finally leaves for awhile and takes the chance to spend time with Pete.

SPOILERS
as hateful as Grayson is, in the extras, Grayson does go out of his way to save Chase. He has his own twisted way of showing his love and care since his brain got fried. Grayson, among all his siblings, had the worst of it when it came to his dominant alpha trait manifesting too early. I was rereading Desire Me if You Can and was reminded of it.
When Chase was dying from his accumulated pheromones, Grayson drove miles to drag Joshua back to help Chase release his pheromones. When dragging Joshua back, he got hit in the wrist with a helmet and ended up with a broken wrist. Ignored it until he got Joshua to Chase first, then got treatment for his wrist. So his love and reasoning is twisted bc as we understand it in Desire Me if You Can, he mentally and emotionally really can't understand emotions due to brain damage. But he does try his best with what he can understand. Chase understandably still hates Grayson and Grayson just has to live with that.