Why instead of OrderNo You just not set a Field family member type:
1 - father
2 - mather
3 -grand.. etc in order which you want .
The Just by a simple SELECT You can order the cursor.

SELECT Child_Table.*,  Parent_Table.[what you want],;
       IIF(INLIST(Child_Table.FamilyType,1,2...),.t.,.f.) AS Bolded;
 FROM Child_Table;
       LEFT JOIN Parent_Table ON Child_Table.Family_no == Parent_Table.Family_no;
ORDER BY Child_Table.Famili_No, Child_Table..FamilyType;
INTO CURSOR PrtCursor

HTH (If I understand you right)