How do deal with my boyfriend who's still grieving over his mothers death that happend 7 years ago?

I have been dating my boyfriend for about 8 months now & our realationship is great, minus the fact that his emotions our tooken out on me from his mother passing about 7 years ago. He doesnt realize how much of a BUTT he is but later on after he sees how upset he got me he starts to apologize. It's starting to become a routine & im starting to get real frustrated. He then starts telling me you shouldn't be with a guy like me but i asked him to stop saying that becuase it was nonsense. Now he's trying to say that he'll just forget about her completly but i dont feel thats right either. Its been getting worse around the time of his mother's B-Day & passing. Though he has warned me that around those times his emotions are to the extreme i wasnt fully prepared. When hes feeling sad i dont know what to say becuase i dont know exactly how hes feeling. He has told me it's harder becuase his mother didnt die of a natural cuase, she was murderd & he somewhat witnessed it. I need to know how to deal with him when hes mad & need to know what to say to him when he feeling sad. Do you think counseling would be a good option? Please i need help i really want this to work!