It rarely feels like a financial decision at the time.

A son needs a deposit for his first flat, and the bank wants more than he’s managed to save. A daughter’s small business needs a few more months to find its feet.

So the money moves. An EFT, a reference line that says “loan”, and a hug at the front door. Everyone agrees it will be paid back once things settle down.

Sometimes it is. Often it isn’t, and nobody minds very much. Parents tend to see it as help rather than debt, and after a few years the word “loan” only really survives as a family joke, if at all.

The difficulty tends to arrive much later, usually when the person who made the loan is no longer there to explain it.

When an estate is wound up, the executor has to account for everything the person owned and everything they were owed. On paper, a loan to a child is money owed back to the estate. Without a clear record of what was intended, the executor is left with an old bank statement and a single word to work from.

That’s where siblings come in. The one who never asked for help may reasonably wonder why an equal inheritance feels unequal. The one who was helped may long ago have come to see the money as a gift, and may be genuinely hurt that it’s being raised at all. There is some truth on both sides, and the only person who could settle it isn’t there to ask.

What makes this so common is that it grows out of generosity. Nobody sets out to create a problem. Intention simply lives in one person’s head, and money has a way of outlasting it.

It’s often harder than it sounds, because the executor is frequently one of the children. So the person deciding whether a brother’s flat deposit should come off his share may well be his sister, sitting at her kitchen table with an email from the attorney that asks, quite reasonably, whether the money was a loan or a gift.

She may remember the conversation differently from him. She may not remember it at all. Whatever she decides, one of them is likely to feel it was unfair, and that isn’t an easy thing to bring up at the next family lunch.

If you have helped one of your children like this, it may be worth putting your intention into words while you can. A short note, a line in your will, or one conversation with your family and your adviser in the same room. So that the people you were trying to help never have to guess.