Taking on such a child demands a long-term commitment and is not an easy task. I applaud you for assuming this responsibility. I understand that you don't want your own family life disrupted and it doesn't have to be. You can best help yourself and him by enrolling you and your partner in a parenting skills class, and/or family counseling (that means everyone in the family). I also strongly urge you to get your brother into a grieving group. Check first with the school counselor. Other resources for groups are funeral homes, hospitals, and hospices.
You say that counseling helps temporarily. Counseling is a process and it will take your brother time to learn new behaviors. It will take you and your family time to learn new behaviors also, but the key to changing what your brother does is the changes you make in your responses to his behaviors.
Professionally, I believe a boot camp would be the worst thing for your brother right now. It will only confirm to him that he is worthless and that no one wants him.