I differ with my FRiend "just mythoughts", in that the only logical relation between JoA and Mary is that of brother, in that it goes to Jesus' pedigree- His eligibility as the rightful heir to the House of David.
It is fairly common knowledge that a man executed by the state would only be given into the hands of a family member. It is equally curious that Nicodemus was likewise involved...
I ask again, is this common knowledge founded on anything factual? What Roman law was this, or if the text has not survived, is there an ancient Roman writer who refers to this strict policy?