How long has your neighbor been on Atkins? The reason I'm asking is that atherosclerosis (clogged cardiac arteries) takes years to develop, not weeks, unless is was the result of a sudden blood clot in which case it wasn't dietary related at all.
You have to remember here that correlation does not prove causation. I plan to low carb for the rest of my life and eventually I'll die. Does this mean that low carb will cause it?
Also relating the 2 deaths and 1 heart attack, I've only heard of one while someone was on Atkins (although I'm sure there have been plenty more) and 1 heart attack. First of all, nothing has been proven conclusively; these are allegations mostly coming from sources that have questionable motives and even they admit that they cannot prove their allegations. Secondly, when you have millions of people following an eating plan, chances are some of them are going to die at any point in time. This would have likely occurred whether they were eating meat and vegetables or a steady diet of Big Macs in many cases; it's a matter of statistics, but again, it doesn't prove that eating low carb caused any of it.