If you can send him a letter somehow that would help keep his spirits higher than otherwise. Programs use the fact they can only contact the family in charge of putting them in the program against them to break their spirit. If he knows that his grandmother is outside doing everything she can to set him free, and just rooting for him in general, I'm sure that would be helpful in the long run. Sometimes when you present parents and pro-program people in general with information that counters their assumptions they get mad as a visceral reaction, but given time to think about it and weigh the consequences of inaction, sometimes might reconsider. I hope this is true in the case with your family member. There are helpful people who read this forum but do not post, so if you put an email address up it might help them get in contact with you. If you want to stay anonymous you can make a free yahoo email account or something similar.
I wish you good luck, well I am really wishing your grandson good luck. To you, I hope that the stress of knowing a family member is locked away in a program designed to strip them of identity and fill them with a newly undesirable facade of personality, is not too much to bear. Be prepared when he gets out that his family situation will be much worse, as some programs are designed for families to disown the child for not complying, and many parents do this without question. In that case, you could really help him out by helping him obtain residence, food and clothing and most importantly some sense that he is cared for by another individual. He'll be in my prayers. Hopefully he will get the help he needs eventually.