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That plant has sustained extensive root damage, it and appears to have caught a fungal infection as well. The outlook for this is bleak. The next time you grow these, just make sure you get palm soil, as it may be a better texture. Be careful with transplanting, and if these came from the soil outside then make sure to dig far enough around to get most of the roots. Be careful not to over-feed them. They don't need heavy fertilization. There are many types of Dracaena, and all of the tree forms will have the same care. Here is an article that will help: https://www.gardeningknowhow.com/ornamental/flowers/four-oclocks/four-oclock-plants.htm

There are many forms of tree dracaena, but they will all have similar care. These articles will help:https://www.gardeningknowhow.com/houseplants/dracaena/

This article will help you in rooting cuttings: https://www.gardeningknowhow.com/houseplants/dracaena/

unfortunately, the lack of humidity could be the issue. These can have a hard time adjusting to a new environment. It could also be rootbound, and need a new transplant. These articles will help:

https://www.gardeningknowhow.com/houseplants/dracaena/dracaena-houseplant-care.htm

https://www.gardeningknowhow.com/houseplants/hpgen/repotting-a-large-plant.htm

It seems to just want a little fertilizer. You can use any all purpose, but I recommend granular or slow release. You may also want to put just a sprinkle of both dolomitic lime and wettable sulfur to condition the soil.

Make sure that you let the plant dry out almost before watering again.

oops "too" tall

The first is a ponytail palm. The second is a variegated corn palm, and the third looks like so many different things that I would not be able to tell you what it was off the top of my head.