The mother, at the end (spoilers?)
I dunno if they're called spoilers when it's like 35 plus years later (lol). And I dunno if it's really a spoiler, maybe more just a heads-up type thing...
But, couldn't the mother be like "you take costudy of [child] & I'll come take him out to lunch once a week/month" or something?? So she could still be able to see him, spend time with him, etc & not be totally out of his life forever? And if something like this may have occurred, they should've at least mentioned it. At the end, it sounded more like she was just sort of like giving up (for good reason) and aside from that time in the apartment was never going to see him again... IMO.