Wow, you seem to be in a lot of pain… have you ever considered therapy for yourself? meaning, seeing a therapist for the purpose of dealing with your pain rather than seeing a therapist for the purpose of helping your son. My guess is that there are deeper issues within yourself and/or your relationship with your husband that need to be dealt with…
Also, from what you are saying, it seems as your other children are traumatized by what is going on at home. have you considered therapy for them so that they can learn how to deal with their emotions in a healthy manner?
My guess would be that your entire family would benefit from therapy, perhaps you can find a family therapist and have him/her meet with your entire family(even if your 16 year old son will refuse to participate for now, you still have the rest of your family to worry about). you can try to find a therapist that is familiar with the Bowen Model or perhaps someone who specializes in Structural Family Therapy and see where that leads you…