Brother has Mars in Aries...but gets mad for a LONG time?

He's usually very calm and mellow, and it takes a while for him to blow up. But once he does, it's SCARY and he gets mad for a very VERY long time. Like one time he got in to a bad argument with his girlfriend, and he got sooooooooo mad that he threw her bottle of lotion on the ground really hard and then the bottle broke in half to the point where lotion was splashing all over the place. Then he deliberately shoved off all the things on the table, threw her laptop to the wall, and slammed the door hard as he walked out in anger. The girlfriend was scared because she thought he was gonna hit her at first, but luckily he didn't. After the fight, he went home and didn't spoke to her or call her for 2 weeks. She would try to call him but he wouldn't pick up. After 2 weeks, everything returned to normal....but he was STILL a little mad, even after all that time.

What makes him mad for such a long time? I thought the anger from Mars in Aries usually escalates quickly? Well...NOT in this case. When he gets mad, he gets mad for a loooooooooooong time.

Here's his chart:

He has a Scorpio moon, which may explain why he holds on to the anger for so long. I'm a novice but I don't see any negative Mars or Moon aspects that would indicate that kind of rage.

I'm betting that you don't have permission to be posting his chart. Please read the FAQ about posting charts. Unless its a public figure, you need permission.

He might get even angrier for even longer if he finds that you posted his chart without permission.

Yes, it's important to have permission to post charts unless they are public in nature, i.e. posted on the Internet such as a celebrity. Moon conjunct Pluto in Scorpio would explain much of this behavior.

I'm still new to reading charts but here is my interpretation.
I agree that the Moon-Pluto conjunction in Scorpio can have a fierce intensity when angered whilst simultaneously needing privacy to assess his emotions and protect them from further "invasion." This need may lend to his not wanting contact as it would risk another unwanted violation of his sensitivity. I'd also like to add that mars is retrograde squaring Neptune which may be responsible for the physical, but indirect aggression he displayed once angered.

Mars in Aries can have many manifestations depending upon the outlet the natal chart provides for it. One factor cannot be isolated when describing the source of behavior. I am reminded of a pinball table representing the chart and planets. Any activity of the ball (situation/trigger) lights up more than one aspect resulting in the reaction displayed.

I think Mars square Neptune has a lot to do with it. All the water planets are known for holding onto things for a long time, so this tension between Mars and Neptune would certainly emphasize that.

Not mention that maybe he was not actually angry all that time!! Mars square Neptune is often ashamed of their anger and feels terribly guilty about it after. Maybe he just felt bad for acting out and didn't know how to fix the situation or if he could?