Social isolation and loneliness contribute to the development of depression and anxiety. Comorbidity of mental health issues in hospitalized patients increases the length of stay in hospital by up to 109% and costs the healthcare sector billions of dollars each year. This study aims to understand the potential suitability of embodied conversational agents (ECAs) to reduce feelings of social isolation and loneliness among hospital patients. To facilitate this, a video prototype of an ECA was developed for use in single-occupant hospital rooms. The ECA was designed to act as an intelligent assistant, a rehabilitation guide, and a conversational partner. A co-design workshop involving five healthcare professionals was conducted. The thematic analysis of the workshop transcripts identified some major themes including improving health literacy, reducing the time burden on healthcare professionals, preventing secondary mental health issues, and supporting higher acceptance of digital technologies by elderly patients.