That you handled his anger is excellent....Let him own it.
Think about his anger like taking the boys to the grocery store. They see candy and start screaming and begging you to get them some. Now you have a few ways to handle this;
Ignore their behavior and deal with the humiliation of shopping with screaming kids! (my personal favorite LOL)
Just give them the candy...Not to good as it rewards bad behavior.
Ask them to hush down...and then you will get them candy....Short term easy fix, not really focusing on the future.
Or D....Trudge through the embarrassment and then afterwards calmly explain that you expect them to be quiet while shopping and that if they are, then you will get them candy. This is really the best one. Expectations (boundaries) are set and then the kids either learn what is acceptable or get no candy.
You have set your expectations (boundaries) up....Now he isn't happy because in the past you crumbled into giving him candy quickly. So now the weight of your boundary is on him....Does he want the candy enough to follow the boundaries or not is the eventual question.