There are alot of guys in jail who will write to ANYONE just to pass the time.  In case his other girls r not there waiting when he gets out he wants YOU to be waiting in line with the rest of them!  I would NOT write him back and I would not send him anything wither!  Once he gets out- take things very slowly to see if he has changed.  Life is way too short to waste on losers!  You need a real man who will love u and respect your feelings.  DROP this loser!