All the individuals should be in one table, say tblPerson.

Typically, you have another two tables to define the families: one that just
holds a record for each family, and a related table that lists the persons
in the family and their roles. This tblFamilyPerson table has fields:
   FamilyID    relates to tblFamily.FamilyID
   PersonID   relates to tblPerson.PersonID
   RoleID       relates to a table of roles (e.g. "Husband", "Wife",
"Child").

That works, but it has some limitations. For example, if you need to send a
mailing to your clients who may be individuals or families, there is no one
table you can use. Likewise, if you give counselling sessions to both
individuals and families, you cannot set that up.

This article suggests a more flexible structure:
   People in households and companies
at:
   http://allenbrowne.com/AppHuman.html
It explains how to set up a client table where the client can be an
individual or a family. You end up with both in the one table, and then
other tables define who belongs to which family and with what roles.
Contains example database.