Well I'm with you on the No support for those who did wrong PERIOD (my son or not) Love yes but no extra support ... so where is the real difference ? I don't know for real ... I'm not in your shoes and it must be very inconfortable, I feel for you ... (but maybe you should avoid to talk about money when it's really about : I'm not granted, grow up !!! This is not what I've taught you, take your responsabilities or you will never change or grow nice and deserve what you get here (the money thing might not be well understood from him or some people ... and those are the words that could be misunderstood and might regret)
Take care. Stand on your ground (that's the real way to help him for good to change his bad ways). But the thing is that in jail everything can happen .... again : in jail everything can happen (even if he woke up - and realised that what he did was so so so "wrong" and that he deserve it = the puporse of jail) ... and if you're not supposed to be there at any time (how could you now anyway) you can still send him the minimum he needs and tell him that you'll be the one who would call every (whatever distant time you feel - and that he can call you when he really needs to and again that you are not granted). You'll be a good mother if he is a good son ... you want him to be at least someone who does not deserve to stay in jail and able as a real man to pay for his mistake like everyone who did wrong)
Of course again I'm not in your shoes and I hope you'll find your own ways to be supportive without him thinking that he can do whatever he wants and still get the attention he does not deserve at the precisse time he ask for it ... Take care ... really in fact I don't know what to say ...