We learn from Caitlin that this behavior of Joe’s has been happening longer that their conversation about Will loving him. Seems like wince he was out of his home he went crazy, but he did set Will up with Aidan, even if he didn’t consciously know they were both gay, their may have been a subconscious recognition. And the anger seems like a lot of internalized homophobia… The big question is who is in the pool? The story seemed to have started with drowned people in a river if I remember correctly, so it may not be Joey.