He's still a vampire, but some sort of new magical vampire who can't be hurt by the sun. None of the other vampires have ever seen anything like it before.
He tells Clary that he doesn't want to be her boyfriend anymore because it's not like she loves him that way anyway. "When I'm with you, I want to know I'm with the real you, the real Clary," (Epilogue.49) he says. You know, the Clary who treats him like garbage.
Luke picks her up, and she asks Luke if he was even in love with her mother.
Short answer: yep.
Clary thinks he should have told her the truth, but it's not like he can turn back time or wake her up from her coma.
They go to visit Ma in the hospital, but Clary leaves Luke there. She wants to see Jace first.
She meets Jace at the Institute and they go get take-out together.
At the restaurant, Clary plans on telling Jace that them getting into a hot-and-heavy incestuous relationship is a-okay with her, but Jace tells Clary that he was "stupid" and "cruel" (Epilogue.148) to her, trying to force her into a romantic relationship.
"I'll just be your brother from now on," (Epilogue.151) he says, devastating her.
She sulks back to the hospital, where a stranger is waiting for her there. Stranger danger.
Clary talks to the stranger, who says her name is Madeleine Bellefleur.
Madeleine says she knew Clary's mother, and that Clary's mother put herself into the coma. She'll never wake up naturally.
But, Madeleine says, "I can show you how to wake your mother up" (Epilogue.168).
And that's the last line. Hope you have the next book on hand!