If it is planted in the ground, and you are sure it is getting enough water, check for mole/chipmunk/mouse damage. Any of those will eat roots.

I have also lost plants when ants set up house under plants. Ants will do this to plants that are potted up as well as planted in the ground.

Yes, check watering, either too much or too little.

These are 3 minis that I like too. Keep on watering them, Orchid Jubilee may still respond. Did you cut off the broken and still attached parts? A little B1 for stress might help out here too. I got kind of a ratty looking plant in the spring and now it's nice and lush and full.

You might also get some Vitamin B1 and put on Vi's Violet. One of my minis did something similar for another reason. As a last resort, this was a favorite of mine, I dug it up carefully and put it in a pot without a saucer with good drainage holes and watered it with vitamin B1 for stress and transplant shock. I continued giving it water every day long after all the canes appeared to die. Two weeks later I got new growth off one of the canes and I gave it some more B1 and I have a rose growing again. It gifted me with a bud and a bloom yesterday. Did surprise me, it's an own root and I thought the new growth would come from the roots.

When I plant new minis out in the garden I put tomato cages around them. This keeps my dog and the cats from laying on top of them and from digging the little plants up.
Leslie