Q.stems on my corn plant dried up
Stems on my corn plant dried up and have dried hollow holes now. There were two trunks and one was rotted or something. I repotted the other. I noticed a few days later that where the new stems were growing at one time were dried up and brown. I went to touch it and it crumbled in my hand and now has a big dried up hole. The top part of the plant still has green leaves but they are not looking very good look soft and saggy. I am afraid it is dying and I don’t know what to do. Please help!

I suspect you may have over-watered your corn (dracaena) plant. Drooping or yellowing leaves indicates over-watering or poor drainage. I recommend that you repot your plant in fresh soil after inspecting (and treating) the roots for root rot. More information on root rot can be found here: https://www.gardeningknowhow.com/plant-problems/disease/treating-root-rot-gardening-tips-for-housplants.htm
Your plant may be past the point of saving but this will give it its best shot for survival.
For more information on dracaena plants, please visit the following link:
https://www.gardeningknowhow.com/houseplants/dracaena/dracaena-houseplant-care.htm