What to do with furry cactus that flopped over. There I'd root sticking up attached to lower end of plant. Can I cut the top off and stick in new cactus soil?
Did it have an injury or did it flop over due to root rot?
If it was knocked over, just resettle the cactus back into the soil.
Root rot is likely caused by improper watering and if it's roots are dead, not likely to reroot and live.
Propagating a Cactus information in the link below.