Rav Dovid Stav, Chief Rabbi of Shoham and head of Tzohar, together with his son Rav Avraham Stav, have written a halachic article for an upcoming edition of Tchumin in which they discuss the issur of Yichud with foreign workers found in one's home due to their work in caring for a sick family member.

According to Rabbis Stav, when a family needs to bring a foreign worker into their home to provide nursing care for a relative, any family member can remain in the house with that foreign worker of the opposite gender along with the patient and still avoid any problems of Yichud via the installation of security cameras or via giving the keys to the home to a third party who would be given permission to enter the home at any moment.

Rabbis Stav say it is a mitzva for the family member to help and be present and in such a situation, yichud should not be an impediment, but these, or other solutions, should be implemented. And even when they cannot be implemented, the relative, such as a son staying with his mother and a foreign worker, should still be there to assist and to be present and can be lenient about the yichud issue but should try to stay in a different room than the foreign worker, and even lock the door to his own room when possible.

In addition, Rabbis Stav also dealt with the issue of yichud between the patient and the foreign worker, when no other family member is present.

Using the example of the patient being an elderly sick male with a female foreign worker. The elderly male in poor health and weak, or another sick patient suffering with physical limitations and is not capable of having sexual relations, would be able to remain in private under the care of the foreign worker and yichud will not be an issue.

Even with a male patient who is not in such a bad and weak situation could still have yichud with his female foreign worker due to the situation of a sickness along with the foreign worker being concerned about possibly losing her job. It would be preferable to have another person present when possible as a shomer, but when not possible the patient can still retain the foreign worker with no concern of yichud.
source: Srugim