Should I talk to husband about his deteriorating relationships?

I will keep this simple. My husband does not keep in touch with his younger brother who has a son born 2001. He has only hung out with the kid three times and is NOT close to him at all. He has stopped talking to his best friend since last year, when I left my H for a month and his best friend sided with me since he knows my H. Last year, my husband mentioned that he feels he is a bad brother. He wanted to write this wordy email to him and I told him that he could do that but actions will make him a better brother. Calling, texting, keeping in touch. Well that was last year. His brother wants to know what is up with him. His best friend is not knocking down the door for his friendship back but he said he will always be there when my H decides he wants to be in his life again. Its all very sad. 

The other day, my H told me that he can't believe that his half sister and his half nieces have disconnected themselves from him cold turkey since 2006. They don't return calls and they don't contact him at all or me for that matter. It was abrupt and I always wonder why. But it does weigh on his mind. So I told him that this should remind him of how he needs to be in touch with his blood relatives, like brothers and nephews before they forget who HE is too. I hear crickets. 

He can easily remember who abandons him but he has such problems keeping in touch with others and also can be very vindictive. He would deny it of course. He doesn't call my Mom, my family, which I understand since he doesn't call his own family. I can straight up tell him that someone is having a rough time and he should call and he won't, sometimes he even tells me no. Very sad. How do you NOT call you family, especially when you have a wife reminding you to keep in touch? I even told him that his brother was very depressed and he didn't bother to reach out. I am the complete opposite and am very in touch with people's feelings and alwayts trying to help someone. I know I am not him and I don't have his issues. Funny is that people, especially elderly, feel he is generous and helpful but his intimate circle, not so much. 

So  my question: should I just let this go and let the people affected tell him how they feel themselves? I have reminded him many times and he even told me he has pushed everyone away. 

He tries to impress so many people yet can't send a simple text to let his blood know he loves them. These are things that he will feel when someone he loves dies. It's such a shame. I know I can't fix everything or even anything. I hate seeing his life decompose in front of my very eyes. He has such potential. He refuses therapy and meds. His choice therapy is tv/laptop and overcompensation. He gets accolades and stroked with his job, since he is an entertainer/DJ. People compliment him so much, but they are strangers. 

What do you think?