What to do about a false accusation?

My husband recently started working as a CNA in a nursing home. He was sent home early today, because there has been a false accusation made against him. One of his coworkers claimed that he stuck a thermometer into the patients nostril. One of the LVNs went with my husband to ask the patient about what happened, and the patient stated that my husband did not stick the thermometer in his nose. They sent my husband home though. Is that standard protocol? What can we do about this situation? Please help. My husband just recently started working, and I can't believe this is happening to us.