The best thing to do is to bring this issue to his attention. You can not expect someone to change if they are not aware that they are doing something. It may be a personality trait or he may have low frustration tolerance.
If you want things to improve, try and talk to him. You don't have to be all confrontational, just say you want to share an observation of yours about how he is at times. Otherwise, you'd just encounter the same thing over and over. At least if you give him a chance by letting him know how you feel, he may start to be more mindful of how he acts.
That is something to ask him about so you know what the motivation behind it is unless it is some kind of a control issue.