Yes, that can be done. Let's assume the mother is the main contact and the father needs to enter a payment on the mother's ledger using his credit card.

It is very easy; however, because of the Privacy Options feature in iCare an additional step is needed. The mother has to share her data with the father.

Here are the steps for it:

1. Using Privacy Options the mother should share her data with the father.
2. Father should log in using his email ID.
3. If the father has a separate account too, then upon log in he'll be asked to select 1 of the 2 accounts - his or the mother's. 
4. Once logged in into the mother's account, he can make a payment using his credit card. The payment will go to the mother's ledger.