What is the ruling on a female nurse washing an elderly man in a nursing home?

It is impermissible for a woman to work in the profession of washing non-mahram men due to the Sharia-based prohibitions it entails, including the viewing of 'awra (private parts), except in cases of extreme necessity, such as medical treatment, and that would be with a man washing men and a woman washing women. Among the prohibitions also is a Muslim woman working as a servant for disbelievers due to the humiliation it brings to the Muslim. Imam Ahmad explicitly stated the impermissibility of a Muslim serving a disbeliever. However, if a Muslim hires himself out to a disbeliever for a specific task, such as sewing a garment, or for work other than service for a known period, then this is permissible.