The name: Easter cactus (Hatiora/Rhipsalidopsis gaertneri hybrid)

If it is a fungus it is usually best to cut off all infected parts. I am not sure if it is an infection, insect/mite damage or if it has been burnt by the sun or a chemical.
Has it been outdoors? Can you see any bugs on the surface (you might need a magnifying glass)?

Hi.
I suppose it is an infection because it is spreading. I don't see bugs.
As you can see the plant is not that big. All the leaves are infected except for the new ones. Some of them very small.

I should remove everything except for the new leaves. Will they be capable of survive if I stick them in the pot?

Thanks!

Yes, they can be rooted. Let them dry for at least a few days somewhere cool and out of strong light before attempting to root them. The wound will be susceptible to bacteria and fungi before it heals, and that takes a while.

Feddooz, snails do that to mine. Norma

Can you post clearer/closer images?

Josh