These stories are not uncommon in Europe, especially in areas where there was little, if any, medical care for people wounded in both of the World Wars. In cases where people did receive some medical attention, it was often decided to leave the material in the human body because removing it or disturbing it would risk infection or further injury.
In the case of Mr. Brown, I am surprised that he had so many pieces of metal in his lower extremity and that he did not lose the leg to infection. Somehow, all of this material survived inside of his body and did not cause blood poisoning? That's remarkable. He was, indeed, a brave man for carrying all of this pain and agony throughout his long life. And it also speaks to what was packed inside of land mines and other explosive devices. They were deviously constructed devices, and many millions of them still litter countries all over the world.