Paul must be in so much pain. I understand your angry but please try not to let that over shadow everything. He didn't set out to sully Robs memorial day. It seems to me he was just in so much pain he could think of nothing or no one but getting away from it. I know the feeling.
I think you need to think of how Rob would feel if he was here, I'm sure if he could help find his brother he would gladly. Try to think of them watching his grave as Robs way of helping his brother.