The bigger plant looks like maybe an Echeveria, growing in low light... rosettes would be more compact and leaves probably a pinkish hue in the sun, if my guess is right. These plants like strong light indoors, like hours of daily sun.
The plant in the OP looks like a goner to me, but I've been wrong about that plenty of times. In doing a postmortem you should try to figure out what went wrong, and what kind of changes you can make to care to maybe improve your odds in the future. What kind of soil was it in? How much light and water did it get? Were there any insects in the rosette that you could see (like little white or black dots)?
It should be possible to propagate this plant from a leaf, if you want to try an experiment without damaging the mother plant too much. All you need to do there is carefully detach an entire leaf (the base has to be intact). Lay the leaf on top of well draining soil in bright shade, and water the soil when it dries out at depth. Eventually it will put down roots and sprout a tiny new rosette, using the stored up energy and water in the leaf to keep growing and make more roots until it becomes independent.
