Definitely another opinion (or re-evaluation) of the medication would be warranted. The stimulant medication will not be useful re: his mood-related behavior and may actually exacerbate it.
One thing I would suggest is a second opinon consult about medication. What medication(s) is he taking now? Is there a family history of any emotional disorders, such as Bipolar Disorder or Depression?
Possible choices could include low dose of risperodone or one of the antihypertensives, such as clonidine or guanfacine. See what the prescriber might suggest. His age limits the options but does not exclude the pharmacology option.
Do you have any suggests on medications that I could ask for? He is young so i'm not really sure what options there are for him only being 3 almost 4. I just know that something has to be done. His therapist is not sure what else to do either since he has made no progress since starting therapy almost a year ago. In fact he has gotten worse. He is stealing, lying, and physically fighting with someone on a daily basis. He thinks hurting people is funny.
He is on methylphenidate. I have PTSD but other than that no one else has anything.