they were careful not to say who the letters were addressed to.... my guess is, a prison groupie... one of those extraordinarily large women who become infatuated with men in prison for crimes against women.. . something in them resonates with something in the prisoner, and bingo, they start writing to each other, then demanding conjugal visits, and all the paraphernalia that goes along with that...
and sometimes, some prison managers let this bumble along, as it makes the prisoner easier to manage.... but.. who knows..
but even so, his story is pathetic and banal and ordinary... nothing unusual or interesting, all of it predictable, and it won't be long before the sister sells a different story about how mum and dad took them to Luna Park every weekend and filled them up with fairy floss, or something similar....