A loan from one family member to another, where it is documented properly, is a small commercial act. It carries an interest rate, a repayment schedule, security in some form. It is the kind of arrangement that a serious family makes carefully, with paperwork sufficient to satisfy a tax authority that the transfer is what it claims to be.
The paperwork creates records. A loan secured against property is registered at the relevant land registry as a charge; the chargeholder is named, the amount is shown. A loan above a certain size, where one of the parties is a regulated entity or a corporate vehicle, may appear in that entity's filings. A loan in foreign currency, depending on the jurisdictions involved, may trigger reporting requirements.
The interest payments themselves leave a trail. Where they are made by bank transfer, the bank records them. Where they are taxable to the lender, they enter the lender's tax return. Where the lender is non-resident in the borrower's jurisdiction, withholding obligations may apply and the corresponding filings are made.
The repayment, when it comes, releases the security and the release is itself recorded. The charge is removed from the property's title, the corporate filing is updated, the bank account closes. The arrangement is complete; the record persists.
The desk understands these arrangements as part of a serious family's ordinary affairs. It reads the records they generate where reading is useful, and it advises on what surrounding visibility a particular arrangement is likely to produce.
Where this picture matters to a client, the desk reads it in detail and considers what considered work is feasible.