Tell him you appreciate his help and generosity. As Bill Gates is your great uncle and you are so pleased that there are such genuinely wonderful people out there helping his business along.
Sounds like the caller I had on my phone a few minutes ago saying he was sooo concerned because my sky box warranty has run out.How would he know as we bought it on ebay for £20. a couple of years ago.
When they phone me to say I have a fault on my computer and they will fix it for me over the phone, I let them ramble on and then I say well, thats clever because I havent even got a computer. They soon go!