Isabelle lives long enough to die an old man, at peace with himself and certain that he is loved in ways that Alec never could have offered him. And yes, he's religious! Raised Anglican but with an affinity for Catholicism, he's sort of bi-disciplinary and even spends a while as a convent sister in his thirties. His religion means a lot to him and if you have any further questions on it I'd be happy to answer!