Several times a day, he would call his daughter, Mary Trinity, to ask in a faint, slightly garbled voice where everyone was — and to beg her to please, please, get him out of there.

Mr. Trinity was caught in a moment. And he wasn’t alone.

The federal government and various health care associations have issued strongly restrictive guidelines to prohibit family members and other nonessential personnel from visiting nursing homes, rehab centers and other facilities with older, vulnerable residents.

“We know there have been challenging episodes with family members, vendors, state survey teams and even a few ombudsmen or postal carriers, not wanting to comply,” Mark Parkinson, the president of the American Health Care Association and the National Center for Assisted Living, wrote last week. As awareness of the coronavirus grows, he added, “hopefully those challenges will diminish.”

But Richard J. Mollot, the director of the Long Term Care Community Coalition, an advocacy group for people in institutional residential settings, said in an email that he was “deeply concerned about residents being cut off from their loved ones.”

While emphasizing the need for extensive precautions, Mr. Mollot said that banning family members, but not employees who come and go — some to second jobs as home-care aides — makes no sense. He also noted that families are more than friendly faces; they help with eating and drinking and with monitoring medications and treatment.