I’d like to think that charles in xmfc still has something to hold onto and unlike dofp, he feels like he lost everything that has meant to him. His powers no longer feels like a gift but curse.
In XMFC, after Cuba, he lost Raven, Erik and his legs all the same time. But he still has others. He still has the dream to build a school for mutants. That’s why he is more upset and seemingly more cheerful. He still dreams.
But in dofp, it was after the Vietnam War, almost everyone who he still feels as family, is sent into war. I’d imagine Raven and Erik have also caused some troubles as well. He would also keep tracks on those who were sent to war, Sean etc. Imagine with his powers, all those pain and suffering exploded in his head. Imagine feeling all his friends, colleagues keep dying. Like how he felt Shaw but only much much worse. And he can do nothing to stop it. He can’t even join the war physically or protect them due to his disability.
I think Erik and Raven also played their role as well. HIs friend, his sister left him when he is vulnerable. The ‘You abandoned me’ was both metaphorically and literally. They left him when a bullet hit him, they ignored him as his school falls apart.
He is all alone with only Hank, the large manor and the phantom voices of past. Maybe that’s why he is more bitter and angry. He’s broken from the inside