Ask HN: Hiring away your best contact at a potential major customer?

I'm in a weird, but good spot. What would HN do? I'm heading up an angel-funded B2B startup. We've got a landing page up and have gotten some press, but we're mostly in build mode and focused on working quietly with a few customers to tailor the system to their uses. So, it's very early stage. There's a customer we'd love to land that would be a great fit and a big win for us. However, our contact there, one of their two decision makers on outside vendors, is also a longtime colleague of mine and has expressed interest in joining up, "going back into startup mode" (his first company was sold in a smallish but fairly quick exit a few years ago to the big customer in question), and heading up our sales and biz-dev. Can I possibly land him AND his company's business? If so, how? Context: I haven't worked together with him on anything, but he's been advising and encouraging me since news of my angel round broke. Shortly afterward he invited me over to his place to review candidates for our first engineering hire and to break down how our business model and pricing would work, based on his own experience in the industry. Those conversations were incredibly useful as he shared actual numbers and helped me understand some nuances in how this industry evaluates vendors that I hadn't seen before. These conversations were also when he asked if we might have an opening for him and talked about how he's had a good run at BigCo. and would like to join up a cool startup and do that again. That was 3 months ago. Based on his advice, I scrapped all the candidates for the engineering position, started over, and found someone light years better than the previous candidates. We're building away and have a few early customers. Meanwhile, we've met with him twice, but in a more professional capacity than I think he might have expected to show off the app and get his feedback on it. And meanwhile, every week or so, he sense me clippings on news that we might want to keep track of, new entrants into our weird little field, new products launching. It's been months since I talked to him one-on-one. Since then, I've brought in a co-founder and a few other people. The co-founder wants to bring him on board, but is very adamant that there's a particular way we have to play this and wants to regulate all future contact we have with the guy. Meanwhile, he keeps sending me clippings. I'm not sure how to respond. I'd love to tell him flat out, "we want your business, but we want you even more. Is there a way we can get both?" But that seems like it could get people in trouble. I feel like Steve Jobs would be able to pull this off. Get his guy, and get a fat contract with his company. Not sure how, though. How would you play this?