Is there anything I can do to revive the stem.
Unfortunately, your photo does not show the stem. I am unable to see the damage.
Make sure that the plant is situated in the correct location, and is cared for appropriately. This means bright, but indirect, light. Make sure that the soil has adequate time to dry down to around 2 inches or so between waterings as well.
This article will offer more information on the care that these plants require:
https://www.gardeningknowhow.com/houseplants/dumb-cane/growing-dumbcane-dieffenbachia.htm
The blooms never open and then just die off.
Many cultivars will flower like this. Usually, the humidity will be too low to sustain them for very long. Just be sure that you are caring for it, and feeding it as it should be. It will continue to reward you with these blooms.
This collection of articles will help:
My dieffenbachia has gotten very tall and top heavy. The upper stems are thicker than the lower stems because of better care in the last five years. The stakes no longer can hold the stalks upright and they constantly fall over. What should I do? If I cut one of the stalks, can I repot it? should I cut both and start over?
You can cut one stem back to six inches from the base. When new growth starts on that stem, cut the other one back to six inches. Here is more:
https://www.gardeningknowhow.com/houseplants/dumb-cane/propagating-dieffenbachia.htm
endants for 57 years. This was a plant that was given to my mother the day I was born and I have kept it's decendants alive for 57 years. I am terrified and have no idea why they are all blooming at once?
It is happy enough to bloom! Here are some articles with more information, though it seems that you have a good idea of how to care for the plant:
Some of the leaves are yellow on the edges.
Yellowing leaves can indicate a rootbound plant. It also can indicate too much fertilizer, overwatering, nutrient issue, or insect problem, so check for those, too.
I think it will be fine if you want to repot. Remove the yellow leaves and just go up one pot size.
https://www.gardeningknowhow.com/houseplants/dumb-cane/growing-dumbcane-dieffenbachia.htm
https://www.gardeningknowhow.com/houseplants/hpgen/learn-more-about-repotting-houseplants.htm
I've had this plant for a long time. Any suggestions as to what exactly it is and what can I do for it to grow. Also my tomatoes are growing but should I put in a bigger pot?
Tomatoes do need large containers to accommodate the growing roots, at least 12 inches deep by 12 inches wide. Here is an article about tomatoes in containers:
https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-pots-containers.htm
Your houseplant is a Dieffenbachia. Here is how to take care of it:
https://www.gardeningknowhow.com/houseplants/dumb-cane/growing-dumbcane-dieffenbachia.htm
I transplanted the Diffenbachia this past summer. The plants are growing well. But the smaller plant has grown two leaves, only one of the leaves opened. The other leaf started to open, but never finished. This has been 1-2 months in the same position. What can I do to get the leaf to open?
Since you have transplanted, recently, I suspect that roots have been damaged. This can take some time to heal, and providing proper conditions will be the only way forward.
This collection of articles will help: