I have a 23 year old son who is mentaly challenged.  He lives in a residintal setting not at home he has started showing signs of aggresive behavor more so lately than ever before.  We have seen several DR. over the years for a truly dignoses but he is as very complex individual.  With some research that I have been doing recently I came across Borderlin Personality Disorder that fits some of his behvor issues is this someting that might develop at this point.
Hi there ~I understand your concerns for your son, and it is difficult to deal with a child that is mentally challenged.  He also seems to have behavioral issues related to the same, and it would be appropriate depending on the behaviors that he exhibits to start him on medications.  A psychiatrist can diagnose and treat the child.  Behavioral treatments may be either through counseling or through medications, and I believe that consult a psychiatrist would lead to the right answers here. I hope this helps.  Take care and have a lovely day!