To answer your specific question...
It sounds like you need filemaker to find a record if the specified data is in Field A OR Field B OR Field C...
You do that in filemaker by creating a separate "request" for each such field. You can do this manually or in a script:
Enter find mode and enter the search data in Field A.
Create a new request (Select new request from the Requests menu)
Enter the search data in Field B.
Create a new request
Enter the search data in Field C.
repeat until you have a request for each such field.
Perform the find.
Note that you can avoid this complexity if you create a table for your "family member" data, relate it to your original table and use a Portal to display these records. Now search all such related records can be done with a single request instead of creating one request for each group of "family member" fields.
Thanks Phil, I shall create a new table as suggested. My biggest problem is inexperience with FM.
Nearly 30 years of programming in Pascal is proving more of a hinderance than a help.