
Certified GKH Gardening Expert
No, it doesn't look good. It may be rotting from the roots up. You can try repotting in fresh cacti soil but it's probably a good idea to propagate. You can cut off a couple of those stems above the dark color. Make sure you only get healthy tissue. Let it callous over for a few days before placing in new container with fresh cacti potting mix.
https://ucanr.edu/sites/mgslo/newsletters/Propagating_and_Caring_for_Cactus28082.htm
https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/overwatering-cactus.htm