Is this good advice to give to someone who is prone to emotional outbursts?

I am trying to determine what to say to one such person.

I would start by saying to acknowledge your feelings. If something makes you sad or angry then acknowledge to yourself that you have these feelings. In many cases the next step is to express your emotions without showing them. You can calmly say, “It upsets me when you…”. Now the other person is obligated to respond, and we have the beginning of what will hopefully become a meaningful dialog.