I meant so he could focus on the MC/Haley relantionship instead of making two paths.
If I misunderstood you again, it's because you do a poor job of making your point clear, but I think I understand what you mean.
You want the dev to work solely on finishing the Sandra part of the story so that he can then work solely on finishing the Haley part of the story sans Sandra. There's a problem however:
The players who are not interested in Sandra would then get updates that are only focused on Sandra and will probably abandon the game. By splitting the updates along the two paths, each update gives at least some engagement to both sides, where that obviously wouldn't be the case if the dev went and worked only on one path and left the other on hold.
If that is what you meant, I still don't think it would be a good idea for the dev to do, too much to lose by doing that.