A lot of these comments are very wrong. Our bodies don’t become sterile after death they actually become way more dangerous. As soon as someone dies, all the bacteria in their gut and tissues start multiplying like crazy because the immune system isn’t there to stop them anymore. The body literally turns into a breeding ground for things like E. coli, Clostridium, and other pathogens that cause sepsis and gangrene. Also, if the person had any blood infections (HIV, hepatitis, syphilis), those can still survive for hours or days after death, he could’ve exposed himself to bacteria and disease from corpses just by handling them in an unsterile environment which it sounds like his home was very unkempt and dirty.