Dissolution and God

I am new to this group and need some guidance, if possible. Over a year ago, we adopted AP who was 2 yrs old at the time. He had immediate problems with behavior (which is to be expected), but he got worse and worse. He has been diagnosed with RAD (reactive attachment disorder) and is getting treatment. Although I stayed home with him for the first 5 months and have hired every service provider imaginable, he and our family are very unhappy. He is a typical RAD kid, whereby he is violent, enjoys bulling kids, abuses the animals, manipulates every situation, lies, and is violent toward his daycare teachers, including choking one. Probably the worst, though, is that he will have 2-3 hour tantrums where he screams like nothing one could even imagine. He is full of rage and very unhappy at our house. Anyway, my conundrum is that we are just beginning to think about dissolution to make AP's life better as well as our own (we have a 7 yr old bio child and am prego and due soon). I am deathly afraid he is going to hurt/kill the baby b/c he enjoys hurting anyone who is smaller than him. So, this whole time we've thought that God led him to us and vice versa. We've prayed more than you could imagine and continue to do so. I don't want to keep him here if he is miserable and could be happier elsewhere. I guess I have the age old question of what does God want us to do. Any advice or suggestions?