That is a form of Cotyledon orbiculata in the Crassula family (Crassulaceae). It is a low, succulent shrub native to southern Africa.
The plant is desiccated, likely because it's stems and roots are compromised so that it can't take up water. Water the plant and look for leaf turgidity and new leaf growth, but also take stem cuttings to make new plants, in case this one continues to decline.
The plant next to it looks fine so I don't think that insufficient irrigation is to blame. That plant is also a succulent: Lobster-claw Mint (Coleus neochilus, formerly Plectranthus neochilus). It has spicily fragrant leaves.