Possibly, but only in the same way that any kind of intensive sports training might help. Martial arts isn't a mystic path to calmness in the face of anything, it's just learning to fight. The real question is whether his anger ever becomes uncontrollable - if that's the case then he needs to sort that out before training in anything where he might hurt someone else if his emotions get out of control.
If you could find someone who teaches meditation and mindfulness alongside martial arts then that might be your best bet. However, my first port of call would be an anger management professional who would be more likely to offer something like CBT. As Aegis points out, if his emotional triggers are likely to be set off during paired work or sparring then the dojo is probably the last place to be.
For what it's worth, I have a problem with anger management, but it's never been the slightest issue for me when doing martial arts. On the other hand, martial arts don't seem to have helped it at all.
I would suggest a good yoga class instead. I've done both martial arts and yoga and in my experience most people in martial arts who claim they are relaxed have simply exhausted themselves to the point where they have to relax physically to move. Mentally, they are still tense/tightly wound. Again, just my experience. Martial arts involve fighting in various ways. Fighting in a full contact art can switch on a stress reaction (fight or flight). So basically a person can temporarily increase their stress levels during sparring. Like others have said, martial arts aren't some magic mystic thing that bring you peace. Any martial arts that claim any calming or spiritual element (like Taijiquan or Aikido) involve a lot of breathing or meditation as part of their training. I would get your friend to look at those elements first to see if that helps.
I've been doing martial arts for nearing on 30 years. The only thing that resolved my anger issues was professional counselling.
Sometimes having an outlet for stored up anger, thumping the hell out of a bag or sparring with an opponent, can help reduce stress and allow an individual time to begin address an issue.
Or sometimes, it can heighten their stress and aggression and possibly not help at all (or make things worse). I think there are better ways (as mentioned by others here) to deal with anger.
In which case stop doing it. To me your comment appears closed minded and unhelpful. Surely what is best would depend on the individual and the particular circumstances of the individual at the time?
I have pretty explosive anger, usually its directed at myself but at times I've unleashed it on other people. Honestly I can say that martial arts helps me, but (please don't kick it) that's just on a personal level. Some people really do not need a violent sport in their routine, criminally violent mentally I'll people are an example but I wouldn't limit it to just them. The runners high is a great thing and no matter how you get it rather its karate or cycling or aerobically doesn't matter just be positive and think about keeping that good feeling.
In case that was addressed at my statement: The idea of doing it wasn't my point, but that you can injure your wrists, if you go and hit a heavy bag or pads, without knowing (i.e. holding your hands correctly etc.) what you are doing. If it was just a comment to the topic, please never mind that post ^^
Anger is usually a defensive expression of frustration or insecurity. Good martial arts training will shine a spotlight on your weaknesses. Bad martial arts will paper over them with fantasy. Neither of those is likely to work out well for a person who reacts in a strong negative way to things that remind him of his perceived flaws.
Not to derail this thread but I have one thoughts about the side topic of pad work. Pad work is good for a martial artist no matter what side of the pads your on.
