Re: chelation
Do you remember if the filling which dissolved was silver (actually it likely would have looked black over time)? If it was, then the mercury will still be stuck in your system. It won't leave until you make it go.
DMSA taken every 4 hours(including at night) is one way to chelate. See the Cutler Protocol for more information about using DMSA for chelating.
I'm not sure if metals are more likely to hit poorer people or not. One possible cause is old pipes with parts made from lead. Perhaps older, poorer homes may still have lead paint in them. It's hard to say since (in my opinion) the powers that be have chronically underestimated the impact of metals on people.
DNA probably also plays a role in all of this. Some people are coded to be better at chelating than others. It's possible that many of your family members are suffering from a buildup of metals because of shared genes. I suspect the same thing in my family.
I was reading the other day that people may be more prone to obesity because their mothers pass their intestinal bacteria on to their children. If the mothers have too much of one bacteria or another, it may make their children more prone to gaining or losing weight and other health issues.