Like other real estate, the timeshare goes to the survivor, if it's in joint name with rights of survivorship. Otherwise it goes to the heirs, as determined by the will or other last wishes document or as determined by state law or a court, if there is no will or comparable document.
Someone who inherits a timeshare has an opportunity to "disclaim" it. In other words, refuse to take title to it. In that case, it still resides in the estate until the executor or other person responsible for the estate administration disposes of it by sale, distribution to one of the other heirs or by any other means legally available to the executor/administrator.