I'm not entirely certain what I'd done to offend you, other than come in to help save your mother's life (which would be the last on my list of things to get ticked off about), but as it seems clear that I have upset you in some way, allow me to offer you a little bit of advice.
If you're going to threaten, in a language other than English, to kill me and my family, maybe you should check one thing first - check that I don't understand what you're saying.
Otherwise, you will be left with only one of two options:
Either you leave the house.
Or I do.
Seeing as I'm the one with the knowledge, skills and equipment to actually help your ailing relative, I would suggest the first option as the more prudent of the two. Acting all innocent and pretending that you didn't say what I heard, or didn't mean what you said, or, more likely, didn't mean for me to hear and understand it, is all a little bit too late.
A moment passes, you stand your ground, shout at all those around you. Even your family know you're in the wrong, that you've been rumbled. They want you out as much as I do, but you refuse to leave, or at the very least, apologise. As I stand up to leave, having made sure to leave the oxygen with the patient so that she suffers a little less, you block my path, holding a fist up to my face.
"I'll kill you if you leave!"
"A second ago you were threatening to kill me if I stayed. Now make your mind up. Either get out of my way, let me out of the house and you can deal with the consequences, or you can leave and let me treat your mother. Your choice, but the longer we stand here, the worse things get for her."
You shout some more, a mix of languages. You push your brother out the way, storm out to the street and slam the door behind you.
After you leave, several sighs of relief can be heard, and amongst them one voice, quiet and muffled by a plastic oxygen mask.
"Good choice, son."