Continue to be patient.
In my twenties I held low paying jobs so my father sent me money every month for rent. I completed graduate school. I am better now 25 years later. I am married and like my job but get stressed easily.

Let the psychiatrist know about the yelling.
Therapy can help at this stage if he is not already in therapy.

There are different kinds of therapy:

~Experiential therapy -- supportive -- patient feels understood, . .
~Cognitive therapy -- helps with learning constructive behaviors, might ask the patience to make a mood chart to track moods and such in order to find patterns that can be chaged.
~Mindfulness-based cognitive therapy --
~Online therapy --
~

If he will not go, go for yourself to help learn coping techniques.

Also he needs this

1. Lots of sleep
2. Daily exercise
3. Clean diet (low sugars and carbs, lots of fruits and veggies.

Have you asked his psychiatrist about blood work (esp thyroid) and possible tests for vitamin or mineral deficiencies?

http://psychcentral.com/lib/vitamins...isorder/000889

http://psychcentral.com/lib/minerals...isorder/000888

M