Oh golly gosh. deja vu all over again. My creds: (1) Step mother of small boys who are now 21 & 23, pretty happy pretty up-front men. (2) Mother of a 12 yo girl, 3 years post-divorce
The boys were 3 and 5 when I came on board. Mom& Dad had had a civil divorce (no name calling, no high-stress stuff like not enough money to go around) and even so JEEZ were these kids mad, without a way to express it or integrate it.
My boy and anger advice is that boys need a way to express their emotions physically that is appropriate, and where possible, constructive. Things like chopping wood (not with axes, a maul and a splitter). We threw dirt clods at trees. We have a small non-chain grocery store--we went to there with a baseball bat and reduced the recyclable corregated boxes to pulp (all the grocery guys came out and helped, howling with laughter--it's a guy thing. We took turns having "temper tantrums" when things were pretty much under control--(you lie on the floor, drum your feet & hands, and complain)--and see how long you can go without laughing out loud.