Aww, that breaks my heart too, if he lived anywhere near me, I'd take him and take care of him. Maybe the person was just lying about giving the dog away to someone else in another apartment as well. I'd try to keep him as well, but if you have no choice, then what else can you do? I know with my parents if I say I'd take care of him all by myself, or just keep him till they find a decent home something along those lines usually works for me. And if I were to say finding a decent home, I wouldn't do it either lol, I'd end up keeping him, because they would grow attached too.
It's too bad you can't keep him. If he's that quiet, maybe your parents won't notice he's still there. LOL!