When trying to understand accounting, it's always helpful to reference the balance sheet identity, thus
Assets = Liabilities (+ Equity)
, and debits and credits must balance.
In this case, one would
$X Loans to family members $X Cash
So that "Cash" is subtracted (credited) from assets, and "Loans to family members" is added (debited) to assets.
The income identity is treated differently as
Revenues - Expenses = Income
So, unless if the "Cash" and "Loans to family members" did not start imbalanced, there was no revenue or expense. A revenue will be any interest paid. The expenses will be any costs related to loaning the money such as drafting a contract or any amount defaulted.
Assets are not liabilities
A liability on the balance sheet is a liability owed by the entity measured, such as a person or a company.
The family members in this case are the borrowers, so they are the ones who must increase their liability accounts like so:
$X Cash $ Loans owed by family members
The lender to family members would not increase liabilities in this case because the lender is not borrowing from the borrower.
Debits, credits, and the balance sheet
Debits & credits must be equal, or an identity is violated.
Debits add to assets and subtract from liabilities (and equity) while credits subtract from assets and add to liabilities (and equity).
If a lender were to try to simultaneously subtract cash from assets and add loans to liabilities to book a loan, the operation would look like this
? $X Cash
? $X Loans to family members
This would cause an immediate imbalance because there are no offsetting debits, but more importantly, crediting Loans to family members as a liability would actually mean that the lender owes Loans to family members.