He does have a good bit of commentary specifically about the children you encounter around Baldur's Gate and how badly off they are, and wonders who's going to take care of them. He also has conversations about what a terrible place the city is and what can be done to fix it - something he obviously wants to tackle if he can. So the writers did try to telegraph the ending in a few ways; some of it is easy to miss, though, and he definitely doesn't outright mention adopting a bunch of kids or running an orphanage.
If you pick a long-lived race to romance Halsin with, you can certainly imagine that the Daddy Halsin phase only lasts 100 years or so and then you're off on other adventures (this is basically what I did in fanfic).
