Damage such as this may be due to cold damage, heat damage, sun scorch or underwatering, perhaps it was a combination of more than one of these factors. The plant may recover with the coming of Spring. Give it bright indirect light and soil with good drainage. The soil should mostly dry before the next irrigation. fertilize monthly with a complete liquid fertilizer.
Consider repotting this plant into a gritty succulent mix. Even though some commercial growers have success using this wood-fiber potting mix, it often isn't the best for long term maintenance.
Variegated Weeping Jade (Senecio jacobsenii 'Variegata' or Kleinia petraea 'variegata'), in the Butterweed Tribe (Senecioneae) of the Daisy Family (Asteraceae), is native to Kenya and Tanzania. It is a frost-tender trailing succulent often grown by succulent enthusiasts.
Despite having a similar common name, it is not closely related to Jade Plant (Crassula ovata) in the Stonecrop family (Crassulaceae).