Describe their actual origin, borrower and obligations truthfully and provide the evidence requested through the official process. Do not relabel the money as unencumbered savings.
Connect the private arrangement to the real payment path
Distinguish lender approval, disbursement and the instructed government payment. A private promise to lend is not evidence that funds have already arrived or that the gift has been completed. Document the repayment obligation itself, not only the fact that a lender agreed to lend: the term, the schedule, and whether the loan is secured by an asset all describe a commitment the borrower has actually taken on, distinct from the willingness of a lender to advance funds.
Where the loan comes from a relative or a private party rather than an institution, put the same terms in writing regardless of the relationship, since an informal understanding between people who trust each other is not itself a documented obligation a reviewer can verify. Where any security interest is involved, identify precisely what asset secures the loan and confirm that description matches the lender's own records rather than a summary written afterward. Keep the disbursement record separate from the repayment terms, since one shows that money moved and the other shows what the borrower now owes because it did.
A lender's approval letter describes an offer, while the borrower's own signed acknowledgment of the terms is what shows the obligation was actually accepted.