continues to remain healthy? Currently, the plant is in great health. It is approximately 42 years old and has extreme sentimental value. Thus, I am seeking any/all alternatives/tips to ensure it's survival. On a side note, I think it was my dog who chewed on it, has not done it since and my dog did not suffer any health issues. Thank you in advance for any help provided.
I suggest cutting it off near a node above the chewed part and rooting it for a new plant.
https://www.gardeningknowhow.com/houseplants/dumb-cane/propagating-dieffenbachia.htm
Will roots begin in water, so I don't need all the medium and hormone you advise? I am going to give away the cuttings and don't want to do all you recommend.
They might. Doing the recommended will increase the chances and number of survival and surviving specimens.
Basically, you aren't guaranteed cuttings that will root, but the more steps you take the more you increase that chance from very low to much higher.
Here are some more articles on the plant that you will find useful:
Plant is too high. New small trees are growing in the same pot.
You can air layer a new plant, then cut the main plant almost to the ground for new growth.
https://www.gardeningknowhow.com/houseplants/dumb-cane/growing-dumbcane-dieffenbachia.htm
The leave were healthy and green, but separating from stalk. I removed them completely. Was this the right thing to do? Other than only 2 leaves turning brown in the 2+ years since I rooted the stalk, there have been no leaf issues. A few weeks ago I found the plant beginning to “lean” precariously and I “staked” it with small bamboo sticks. Is all of this normal or should she be repotted, cut back, fertilized, or something else?
This sounds like an issue with the plant being rootbound in its pot. This can be corrected in one of two ways. The best way is to repot in a slightly larger pot while gently shaking away old soil on the outside of the root mass and refreshing with new soil.
The more invasive way will be to remove the bottom 1/3 of the root mass and plant back into the container with fresh soil at the bottom. I do not recommend this for the species in question.
https://www.gardeningknowhow.com/houseplants/dumb-cane/growing-dumbcane-dieffenbachia.htm