As sad as it is to say, they might both be doing exactly what they need to to be able to move on.
The way I interpret Sven, he's been holding a candle out for Faye for a long time. Its been eating him, the pain and confusion from it keeping him from acting like he used to, no sex in months, things like that. I'm not saying that isn't a good thing, it led to more acceptable behavior, but while that kind of personal entropy can be healthy for awhile; if there is never -closure- to it, it can become just as unhealthy if not worse. Was it at the worst possible time? It really was, but life seldom happens when we'd like it to. It was something he needed to say to be able to move forward in his life. Sven's projected expectations for the outcome of the conversation weren't reasonable but I don't believe he's unaware enough to know that, he needed to hear it to solve the dichotomy between the knowledge that he'd never get back with Faye, and the hope that there was a way.
Sven's douchiness is part of his persona, as a sufferer of severe depression, even when I'm feeling truly terrible I'll still project a happy face, I've had friends for years that still can't believe I'm depressed because that smile is my armor from it, a personality I can hide behind. I see, or at least hope I see that in Sven. Being a douche is what he knows how to be, he makes his living being a douche. Douchebaggery is something he can throw on over everything else so he can at least have that level of control when the rest of life is out of it.
He also might just be a total butt, but I truly hope this is just part of his road to recovery. I like Sven in a totally unreasonable fashion.
Dora isn't wrong to be distancing herself, she has too much on her plate to deal with Sven. With her own relationships and workload having a random drama factor with the magnitude on her life that her brother has is terrifying. Its like hearing your GM rolling an extra D20 from time to time and knowing if it lands on 1 SUDDENLY SVENPOCALYPSE. It is hard to function knowing that something like that can come swinging in. Cutting that out could be healthy for her. By making the choice she has that much more control over her life, which isn't a bad thing. It only becomes a bad thing if the behavior goes to an extreme, and she starts abusing that means of keeping order. Everything in balance.
I think it might be healthier for Sven, too, not just in the wake up call type of way(Though that is a factor too.) I don't recall Dora and Sven having a lot of positive interaction, and if Sven really is going to move forward I think he needs positive interaction. Negatives will convey something is wrong, but aren't a replacement for real empathetic guidance.
I could probably flesh out my opinions more, but I already feel kind of rambly. Thanks for reading.