simnetpratt, you make sure that whenever you are able, be it one year, five years or ten years down the line, you present this outstanding gentleman with a wonderful gift to thank him for this generosity. You estimate $10K so I suggest a gift of the value of at least $3K whenever you can. A wonderful watch, vintage car or a case of 21 year old single malt. Just something, no matter how long it takes. If I ever make it big or win the lottery, there are a few people I am going to track down, even if I have to hire a P.I. to let them know I have not forgotten them.
There's a lot made of paying your debts, maybe too much for those who hide behind it when what they really mean is "Give me what I am owed". I don't care how many beers a man owes me if he is unable to pay them back but treats me with respect. But some genrosity takes a lot of repaying and through the years a few people have helped me out in ways which were so important I would not be where I am today without them.
To the gentleman who gave this gift I raise a glass to you right now sir. [Wild Turkey 101 in fact, raised to my laptop screen]
May you be happy always.