It does sound like a sticky situation. First of all – I don’t have kids yet, so my 5 cents is just an opinion, please don’t take it as anything else.
I can totally understand how a stressful situation like this can cause you to lose your focus. But look at what you have already accomplished – 60 pounds!!! I’m sure there had been other stressful situations there along the way, maybe not quite as stressful as this, but you’ve managed them anyway. Just draw on those experiences. Think about how you handled it in the past and apply the same strategy, just make adjustments.
It sounds to me like you have a good kid there. He is doing what most teenagers do so well – he is being a teenager. I wouldn’t tell him not to come back if I were you, it puts too much pressure on already tense circumstances. Plus you will feel guilty about it and I don’t know about you, but with me guilt is a BIG binge trigger.
Stay strong and remember one thing – parenting is one of the hardest things we as humans get to do in life. Don’t put too much pressure on your self. Nobody is a perfect parent, you just do the best you can with the circumstances you are given.
I hope this helps a little.