My elderly aunt and I live outside Israel . I am her only surviving relative and I have been appointed by a court there as guardian for her health and financial issues. She owns a property in Israel registered in her name, which needs to be sold to finance the heavy monthly bills at the nursing home where she lives. Is this possible and what is involved ?

Yes, this is possible. You will need to get the foreign guardianship order and other associated orders recognized in the family court in Israel in order to sell the property.  It would be wise to get specific permission and instructions from the foreign court to sell the Israeli property in order to finance your aunt's nursing and other costs. You will need to get the appropriate authorizations overseas so that the court orders will be recogizable in Israel, and you will need to get an authorized translation of them into Hebrew, preferably authorized by an Israeli notary, before you apply to the Israeli family court to recognize and enforce the foreign orders, to sell the property, and appoint local counsel  in Israel to act on your behalf, to handle the sale and registration of the property.