What about peppers, squash, cukes?
Yes, your entire garden can benefit from Epsom Salt applications.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/epsom-salt-gardening.htm
https://www.gardeningknowhow.com/lawn-care/lgen/using-epsom-salt-on-grass.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/epsom-salt-for-pest-control.htm
I have a friend that has a garden and has been planting tomatoes in the same space for 10 years, and he has problems. What can you do if you can not crop rotate? Can you do anything to the soil?
You could move your Tomato plants to containers.
https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-pots-containers.htm
Soil can be treated by sterilizing.
https://www.gardeningknowhow.com/garden-how-to/projects/how-to-solarize-garden-beds-to-eliminate-garden-pests-in-the-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/sterilizing-soil.htm
Last year at this time I had hundreds of tomatoes. This year I am getting 1 to 3 tomatoes per plant. They were fertilized and are watered regularly just as last year. The plants are very large and have buds everywhere. I have not seen any bees but never saw them last year. The plants look good but just are not producing. Any suggestions?
The warm weather and lack of pollination can both be factors.
Make sure your growing a variety that will be successful in your growing zone.
These articles will help you address these issues.
https://www.gardeningknowhow.com/edible/vegetables/tomato/hot-climate-tomatoes.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossoms-no-tomatoes.htm
some leafs are like the pictures?
This is pretty typical to see some yellowing and curling. Tomatoes are very expressive when it comes to their environment and will let you know that something has changed.
Most of the time this is of no concern. Sometimes this coloration can indicate an Magnesium deficiency on the lower leaves. This can be corrected with Dolomitic lime, which provides calcium and magnesium, both.
This article will give you a good run down of what a healthy tomato plant needs: https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-guide.htm
tomatoes are dark almost black on the ends. what does this mean
This sounds like Blossom End Rot; this article will help you,
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossom-rot.htm
I bought 4 healthy tomato plants (4" pots) in May, repotted them in larger pots with regular potting soil and soil with worm castings. Then I put them in my southern window. They grew and grew...and grew. 5' tall now with no flowers and no tomatoes. They look great as greenery for my window but I wanted tomatoes! I can't plant outside. What did I do wrong?
This sounds like a lack of light. A Southern facing window will not be near enough light to get a tomato to produce fruit. You will need to add, at least, 200 more watts of supplemental lighting to achieve a decent fruit set.
Along with lighting, they also have a heavy feeding requirement, which will not be met with potting soil alone.
This article will help you to grow tomatoes in container: https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-pots-containers.htm
This article will give you a good rundown of the requirements for a good crop of tomatoes: https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-guide.htm
Tomatoes are planted in large containers, 2 plants. Every tomato has blossom end rot. I verified with my nursery as to the problem.
This article will help you.
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossom-rot.htm