Since this week has made it abundantly clear that Faye will not be magically cured of her alcoholism, and that she has a lot of stumbling around to do: Any thoughts on the possibility that she turns to Sven in a moment of weakness, and he becomes an enabler?
Consider the following scenario: Faye fails to make it back to the straight and narrow, so she can't pay her half of the rent, and eventually loses Marten's support. (Alternatively, Faye begins to resent being baby-sat, and moves out of her own accord.) She will need a place to live, and she will prefer the assistance of someone who isn't ready to judge her for drinking occasionally constantly. Enter Sven, who has the means to put Faye up, lacks the moral backbone to be firm with her, and remains infatuated after all this time.
If this sounds like a terrible course of action for both of them, that's because it is. There is no possible way for either of them to remain happy in this arrangement in the long term, and coming out the other side with their dignity intact is impossible. But such minutiae haven't stopped these two before, and they're both far too stubborn to learn things any way but the hard way.