I'm kind of surprised that I didn't think of Love and Logic, but Rosemond is very similar to L&L, with a little extra snark on the side. We go to a really wonderful play therapist whose philosophy is very L&L, with absolutely no snark.
L&L would say that in situations that are dangerous either to the child or to someone else, the parent should intervene very firmly. This can include isolating the child (time-out separate from the family and friends), or in can include taking away toys, privileges, or imposing extra chores. L&L would say no lecturing. Just calmly impose the consequence. You can say something like, "Boys who are civil to their brothers get to watch tv," or something like that.
I remember that for younger children who hit, I've seen advice to lavish extra attention on the injured child when the aggressor can see.
To me, the throat-grabbing behavior seems a bit more intense than what I've observed, but since I'm an outsider, I don't know what goes on in other families' homes. I did have a rage problem as a child. I wish there had been more awareness of this so that there could have been intervention. For me, I think it was about having an older sister with Downs who would lash out at us, and who was absolutely inviolable. I wasn't supposed to hit back under any circumstances, and her irrational, primitive behavior often made me extremely frustrated. I probably took it out on my younger sister. Maybe your son is upset about the baby?
Be sure to get your dh to speak to ds about this. Sometimes they only listen to a man.
Keiki's Makuahine (Keiki's Mom) 51, dh 52
Keiki: b. 2002 after 3 months bedrest
Natural conception following ZIFT/chem. pg
Olivia: b. 1999 d. 1999
28-week preemie, ptl cause unknown
Natural conception after 1 mc
ttc since 1998