Same problem here. Unlike my Arcane Warrior who stays standing, when Low Brow Dwarf gets mobbed by 3 d00ds, he drops like a sack of potatoes. I'm not really into micromanaging during combat, so I managed to set up properly the tactics for Emo Archer with Daddy Issues, & also Sarcastic Reluctant Mage, but Low Brow Dwarf remains a problem.
Also, my game won't progress past the smuggler battles on the streets of Amarantinewhatever since it crashes straight to desktop. Is this the end of my DA:A sojourn or is the game afoot?
He kept getting killed in the main game as well, so at least he's consistent.
I had similar issues with him, but don't think I managed to get anybody else killed more than once - he might have bitten it 5-6 times.