Might try the county health department. Was it at the doctors office or hospital?
If doctors office he’s calling his insurance company and lawyer and probably won’t respond. There should be a way to determine who the other patient(s) were and find out if they had a communicable disease.
The doctor file s bbb pathogen report and draw your daughters blood now and again for the next 6 monprobably wouldn’t hurt to take gamma globulin. Hepatitis vaccines? Probably yes.