I'm not altogether certain Harry 'forgave' Dumbledore, but he knows the reasoning behind much of what he did, and understanding has to begin there. Also, he's reunited with a family now, and finally has the person in his life that's been missing for the past ten years. I do believe there can be a resolution to emotional trauma, especially when there is a strong support system. And if Harry does 'erupt again over it all', he won't be alone this time. That makes all the difference.
Glad to hear you liked the rest of the story. Thanks for reading and commenting.