Tell someone they're narcissistic?

Hi everyone,

Sorry this is going to be a long one.

A few months ago, my ex ended our two year relationship with little explanation. He was cold and very inconsiderate when he did it, and since this wasn't any new behavior on his part, I decided to take it as an opportunity to figure out my own life and get on without him. Of course, a month later he wanted to get back together and was enraged when I told him that no, while I love him, I won't ever be in a relationship with him again. The next day he called me apologizing and begging for me to take him back. I have told him no repeatedly, but he is still calling me, sometimes just to talk and see how I'm doing. I recently realized that he displays a lot of signs of a narcissistic personality disorder and I'm wondering if there's any point in gently letting him know that. I still love him as a person and I don't want to see him ruining his whole life if there's any hope for him to get help. He has a 5 year old son as well, and I want him to have a healthy relationship with his father. So, should I mention that he needs therapy? He did acknowledge that he was inconsiderate and that he should have thought of my feelings, but I don't know if he really meant it or if he just thought it would help get me back.

Thanks