School application form, two students with same parents info

Hi,
One of our clients want admission form for a school website that does the following:
If someone is getting admission for two children then the parent/guardian has to fill parent information twice in each child application form at the moment.
The school want this process in such a way that the parents have to type their info once and they don’t need to type their data for the second or third child and only type second and/or third children’s data.

If I use any form builder plugin, that won’t allow me to type new record (child) and select parents data from previous record.

One way is to use the general functionality of WordPress by registering the parent and then the parent can insert one or more then one child record by filling the admission form and in this case every child will belong to the right parents. Does these form builders use the data of currently logined user or not? If yes, which form builder will be the best for the above scenario?

Any suggestions and help will be appreciated.

Thanks,
tpd