This story is based on the theory that Remus is in truth James. So if James is still alive how would he feel after hearing Harry saw Snape's worst memory? Maybe it would go something like this....

As Harry's head disappeared from the fire in 10 Grimmauld place the form of Remus Lupin rose from the floor and started pacing in fury. Sirius could do nothing but stay still on the floor and watch his best friend pace. "James-" James lifted the hand of Remus Lupin and shook his head to keep the silence at bay while he continued to pace in the body of the werewolf who was in truth dead, leaving James Potter in his body. Again Sirius started to talk "James we were 15! And do not tell me Snape did not deserve every bit of it." The body of Remus Lupin turned suddenly and snarled at Sirius. "We were conceded berks. I made Lily sick that day and I made my only son sick of my memory! Do not try to calm me Sirius Black because it will not work!" And with that James stormed from the kitchen and made his way into his own room slamming the door in frustration.
Sitting on the edge of his bed James put the head of Remus Lupin in Remus' hands and felt like weeping. He wanted nothing more than to tell Harry the truth of who he really was, to comfort him and more than anything give him a better home then what he had. If anything ate at his conscience the most it was that he was not truly the one who died. What if he had been there instead of Remus in his body? He could of done something more, save Lily and Harry. Without a moment's hesitation he began ripping the room to shreds in his anger. After about a half an hour of ruining everything available to him he collapsed in the middle of the wreck on the floor. He had failed not only Harry but Lily as well and now to top it off his son hated him.
Again he covered his face with his hands and began to weep bitterly. What he wanted nothing more in the world was to have Lily back with him. She was his other half and he just didn't know how much he wanted to go on without her. He was always so close to his son, yet so far. It was heartbreaking to see your own son go to his godfather when his true father was so close and yet unable to help. It was not planned to happen like that! James was to find the turncoat and solve the "problem" not have the traitors win! The life that Lily and he had wanted was destroyed in a matter of moments. It had ended in the flash of a green light. A light that was the same color as the eyes of the two people he loved most. After a few minutes he was able to get himself under control and took a few calming breaths. Suddenly he knew that he had to go on. Remus had willingly switched bodies with him for a reason, not to just mop around and be ungrateful. Somehow James would prove to his son that he was more then a bullying toe rag....and those words brought a sudden pain to his heart. He could still hear Lily's dislike when she called him that on that fateful day. Yes somehow he could also remember the few good times the once happy family had shared. Closing his eyes he could see Lily in his minds eye perfectly, laughing as she held Harry for the first time. She was holding their child, something they had both made and had planned to share. Suddenly his lips curled into a smile as he remembered that first night the three of them had spent together. "Remus! Dinner is ready" The voice of Molly Weasley came from downstairs. Wiping his face on the sleeves of his patched robes he took a deep breath and composed himself. Once he walked out that door he was no longer James Potter in disguise but Remus J. Lupin and he had to act as such. He might have let Lily, Remus and even Harry down once but he would not do it anymore.