For whatever reason the lowest stalk on my green finger leather is disintegrating and part of it has started to turn black.

The coral branches off into three main stalks and the back stalk is connected to another chunk of rockwork.
I'm thinking I need to frag this poor sucker ASAP and am also wondering if it would be beneficial to lop off the three large stalks into separate pieces before the entire coral goes necrotic? I would really hate to lose the centerpiece of my tank but it'll be even worse to lose all of it! Any advice is appreciated. Thank you as always for your help, guys.
Will post a pic soon.