My partner and I have lived together for the last few years and during that time we have occasionally asked her father if we could borrow money, ranging from $500 to $5000 (roughly). The reason for this has always been something significant and (as we see it) non-frivolous such as moving house or applying for Visas ( I am from the UK and she is from Canada).
Typically her father will suggest that we save the money until we can afford to pay him back, and then pay him back in one lump sum to make things simpler, especially with fluctuating exchange rates. However, a couple of times he has decided that the loan no longer needs to be repaid, and usually frames this as a Christmas or birthday gift.
This is obviously greatly appreciated and has helped us tremendously over the years. However, I am due a significant (~$5000) bonus in the next few weeks, and I would like give some, if not all, of it to my partner's father as it would go some way to clearing my conscience as I am always uncomfortable borrowing money. I am aware that that in his eyes we no longer owe him anything as the money is now considered a gift. I want to make sure that if I give him any money, it is not seen as an insult, in the same way returning a gift would be.
Is there a way to pay back the money without causing any insult?