Homo Homini Lupus est

Sherlock doesn’t understand why the coffin has to be so big, the little pieces would easily fit in a much smaller coffin and he wonders how they can be sure the shreds lying in the coffin are actually parts of Daddy. Suppose there is a piece of Mr Norton lying there in the coffin as well, or Mr Percy-Fitz or Miss Lewis, the other people that were blown up together with Daddy?