Revive a Trichocaulon?

[A4Gardner]

Last year, my Trichocaulon cactiforme grew very well. It's in a greenhouse in the UK (South). It survived the winter with the greenhouse being kept above 5 C. I started watering in late March with small amounts of water. However, I noticed it wasn't plumping up, and when I inspected the roots I could see they looked dead - they looked dried more than mushy rotten.

It there any chance I could revive this by cutting off the bottom part, letting a callus form, then trying to 'strike' it? Or has it been lost?

[esp_imaging]

It doesn't sound like you need to panic - if there's no sign of rot, why do you need to cut the base off?
It may come back to life anyway as days become warmer.