Golden Barrel Cactus
I have had this golden barrel cactus for years and now it is starting to die. I don't think there is any saving it. It is caving in all around the bottom and spreading fast. I have seen these die with little ones that sprout on the dying one. How does that happen, as I would like to carry out the legacy?
Cacti can be infected with fatal fungal rots, and look perfectly normal for months. Then they start to collapse, as if a leak was letting all the air out, and proceed to collapse in a few days. If you had pups already sprouting, you could cut them off and root them, but if they're not already there, it's not likely they'll sprout from diseased tissue. You don't mention if the plant is potted or in the ground, but in either case the most likely cause of the collapse is too much moisture in the soil, or insufficient drainage of the soil. This article might help you with your next attempt: https://www.gardeningknowhow.com/ornamental/cacti-succulents/barrel-cactus/barrel-cactus-care.htm