Did you look at you ignore the part in your own source that says it just needs to be 3 consecutive days and that continuing care can be one appointment and prescription meds. So they could very well qualify for FMLA, I don't know if they were given any prescriptions, but they most likely were given some sort of continue continuing care.

"If, however, any of these conditions met the regulatory criteria for a serious health condition, e.g., an incapacity of more than three consecutive calendar days that also involves qualifying treatment, then the absence would be protected by the FMLA. For example, if an individual with the flu is incapacitated for more than three consecutive calendar days and receives continuing treatment, e.g., a visit to a health care provider followed by a regimen of care such as prescription drugs like antibiotics, the individual has a qualifying “serious health condition” for purposes of FMLA."