Collapsing, mushy and soft cactus

[okonek83]

Hi,
About a month ago I got a small cactus. It looked normal and healthy. I was watering it about once a week but in very low amounts. About a week ago I noticed that it started slowly falling in/collapsing and getting darker at the bottom of its stem. I took it out of the pot to change the soil and the roots looked ok.
Now, the the darker coloring has spread higher and the whole cactus is so soft that I couldn't take it out of the pot if I wanted to. Also there are a few white, kind of dotted spots. I tried brushing them off with a paper towel and a stick but they don't come off.
Also, the spines are very delicate and a few have fallen out because of some light touching.
Is there anything I can do to help my cactus or is it totally dead and not worth to try saving?
I attached some photos of the cactus now and a month ago.
Thanks, Janek

 

[Chuck]

Cut your watering to maybe once per month. I have that same little cactus growing wild on my property and they only get watered when it rains, which isn't very often. But, if it is becoming soft it is probably too late.

 

[DirtMechanic]

@zigs?

 

[zigs]

Welcome to the forum

I think it's too late now I'm afraid.

Cacti don't need watering in the winter months, I've only just started watering mine a week ago. I water once a week from April till September, unless the weather has been grey, then I wait another week. They must dry out between waterings and need very well drained soil.

Don't give up, I drowned my first cactus when I was 8 years old, I got some more though