He shouted at you this morning over a buttoned shirt, and the sting of it is still sitting in your chest. This page is about anger that is still words, what it is usually carrying, and how to keep it from becoming more than words, and if it already involves hands or thrown objects, go to the aggression guide now, since that page owns the moment this one works to prevent.
Before you say anything back, notice what the shouting did to you, whether it is the heat rising in your own face or the urge to match his volume or to walk out for good. That is yours, it is normal, and one breath before you answer is the difference between two people yelling and one.
Before you read his anger as the disease, or as something about you, run the pain guide's checks and the day's basics, since yelling that arrives with the sleeve is often the shoulder talking, and an arm that hurts on movement has no other way to file the complaint.
Anger at helpers is rarely anger at help. It is what fear, overload, and lost control sound like when the words for them are gone. Help that arrives too fast, from behind, or unannounced lands on him as invasion, since his world now processes at half speed while your hands move at full speed, and instructions stack up faster than he can clear them until the only thing left in reach is volume. The man yelling about a shirt is usually yelling about something the shirt is standing in for, which is that his morning is being done to him rather than with him.
There is one more honest thing to say, and it is about you. Being yelled at by the person you are helping wounds, and the wound is real even when the disease is the cause. If you have yelled back once, or left the room shaking, you have not failed at this. You have been a human being doing the hardest unpaid job there is, and the rest of this page is built to make tomorrow morning go differently, not to grade yesterday's.
Print the one-page log if you want somewhere to keep this, and take it to the appointment.
This is what the tracking is for. A dated trigger log turns "he yells" into which task, what time, and what came first, and that is the shape a doctor can act on.
The shirt will still be there in twenty minutes, and so will you. What ends the shouting is not the right words but the slower hands, the quieter room, and the willingness to stop before he has to make you. You are allowed to lose the task and keep the morning.