What i can do to cure this Mamm.?

[taskan]

I found it has fungus and has been rotten

Should i cut down my cacti?

picture

[mdpillet]

Looks neglected. Cut it off from the graft, cut away the rotting parts (better too much than too little), treat with an insecticide after a couple of days (you don't just have fungus), wait 2-3 weeks, repeat the insecticide, then treat it like any cactus cutting. The soil also looks quite poor for cacti. Look at some of the care guides on the website.

[taskan]

Thank you, it can be helped :"(
But i save all the offsets