Hi Angelina. I think it’s too late for these guys. I don’t know what kind of light they are getting or how often you water but what I can see is that it looks like they needed to have a more porous, better draining growing medium.

The Gynocalcium is grafted to root stock since the plant on its own has no chlorophyll so can’t produce its own food. I think they look cute in the nursery and people sure do buy them but they never seem to last very long once people take them home.

I have no idea what the other one is. Sempervivum, maybe...?

I’m sure someone else will chime in, but pretty sure these are both goners.

I’m sorry. Try again & better luck next time.

It looks like both have rotted from the roots up. The gymocalcium may be able to re root. You'd cut it off above the brown to green line, leaving only healthy firm green. Let it callous in shade and hope that new roots grow from the green. No water at all until you see new roots. The other one looks to be gone, not enough green left to reroot. Likely both perished from poorly drainig soil and/or over watering.

As SoCal mentioned, the Gymno won't survive without being grafted. Buy new plants and forget about these two.

Looking at the grafted Gymno, looks like maybe the rot stopped. The line between the dead part and the living part looks well defined but being sure is a bit tricky with rot and photos. You might be able to remove the bottom dead tissue, repot the living part of the rootstock, and reroot it. However, the scion, the greenless grafted Gymno on top, already looks iffy and I'm not sure the shorter rootstock will support the needs of the scion. I think my idea is a long shot and the easier solution is to get a new plant.