I'm surprised by what he said since he mentioned he went through it with his daughter and lost his wife to drugs. Why doesn't he know that sometimes you have to let go of it all so that they can get better? Since he said he would contact you again I hope that he rethinks his opinion.
All you need to know is that you love your daughter, he doesn't have to be convinced of it. I'm glad his daughter is sober (thats what I got from it anyway) but we all deal with it alittle different and he should know that.
You're a good and loving person, don't think on it too much.