How do I re-raise a soon to be 3 year old?

I am new at being a parent. I basically just jumped into being a parent. My boyfriend is in the Marines so he is never really home. His son who is 2 has been through a lot. His mother has a few mental illness problems. When Nate (boyfriend) has gone on deployments she never really took the right roll of being a mother to Calibur. Calibur never learned how to be calm because the mother seemed to be angry all the time as well. Cal himself seems to be angry all the time. I am trying my best to be that mother figure that he never got to see. Basically I am trying to get caught up with rules and manners. He is doing better so far. I couldn't be anymore proud of how long hes came since we left home (Seattle). I guess I just need advice on how to start over on raising an angry 2 year old. I give him my attention and love so he understands that there is no reason for his behavior. He can play and have fun without having to be sad or upset. We go to the park almost everyday so he can learn to play nice with other children. Hes improved on that. He used to kick and push and spit in other kids faces but I always had to pull him aside to teach him that its not ok behavior. In the process of all of this there is also a 10 month old, He is a good baby. I love these boys like they were my own. I need all the advice I can get to this new world of parenting!!