as you mentioned, we can design household member as sub-form for each member but in that case each sub-form can not be linked and depended on each another.
For example, If mother is 25 years old and we filled one sub-form entry. For her son we will fill next sub-form but when they enter age of son as 20 there should be error saying the age difference between mother and son is 5 years which is very less. Please correct your entry.
I have customized and designed HTML page which look like following
The UI works nicely but I don’t know how to save the repeated rows in database and also when i edit the form it does not displayed as i filled.
Note: In the ODK 2 tools, we have eliminated the concept of a repeat-group. (ODK-X documentation — ODK-X Docs)