The good news is that once N got past that initial weight-loss, he has held steady. We agreed upon 185 weight which is a reasonable weight for him. He has been good about catching the bounces and not letting himself drop.
There was a period of time where his roommate with the scale was transferred away. It's no surprise that N assumed he was gaining tons of weight when he was actually losing. Once we insisted that he find access to another scale, he acknowledge the weight loss and got right on top of putting the weight back on.
He seems mentally stable and well. He said that there have been a few struggles with OCD stuff, but I bet that is completely associated with the drops in his weight. It would be wonderful for him to put on another 10 pounds just to give him a better buffer from sickness or something like this, but this is a liveable goal.
He'll be home in July for just a month and then he'll be off to college. He's been able to live independently for these past two years. I think if we continue to have him regularly weigh himself - and be accountable to us - he'll be able to thrive without any additional relapse. One other good thing is that some living conditions will improve upon his return home. Also, we'll be nearby and can easily send food and/or money if needed.
My one question is about him weighing himself. For so long, we were told not to let him do that. But it seems to be working. I wonder if there isn't something that I'm not considering, though.