Scientific evidence shows that the microbiome has an impact on the mind. In fact it is to the extent that scientists call it the "second brain". Yet it may even be more accurate to say that it is the seat of the mind. The vagus nerve from the gut communicates 90% from the gut to the brain and only 10% from the brain back to the gut. And there are more microbe cells in the body than human DNA cells. Perhaps the brain is just a power plant/communications routing system which is used by the microbiome.
After death the microbiome lives at least unless the person is cremated. So in order to have life after death you should choose burial. That way the microbiome i.e. you will continue to live after its vehicle (your body) dies.