Q.Save a dying Aurora Lavender Delphinium
Hi – I bought a gorgeous Lavender Delphinium earlier in the summer. I didn’t transplant it soon enough and it started to dry out. So then I transplanted it into a self-watering pot, forgetting to remove the bottom. I went away for a week and had someone come to water for me. When I came back, the plant was almost dead, I realize because the water wasn’t draining and I think the roots are now rotting. I’ve transplanted it a second time into dryer soil and cut off all the dead stalks. Is there anything else I can do to save this plant? It was expensive and just beautiful when I bought it. Thank you!

No, you will just have to wait it out and see if it grows.
Good luck.
https://www.gardeningknowhow.com/ornamental/flowers/delphinium/growing-delphinium-plants.htm