"Can a remote client access my EEG Expert account and see my other clients".

No, Under no circumstances does the client password give access for your therapist account.

Make sure to LOG OFF of your therapist account when finished.

If you connect to a client remote tracking session without logging out of your clinician session in the same browser (e.g. another tab), you will not end your clinician session, in this way it may look as though you are giving a client more access than you intended. Make sure to LOG OUT when finished using EEG Expert.