If you go down this path, respect this person’s boundaries. I’m not encouraging you to get drunk with your friend and make a move. How about grabbing beers and saying something coy, like “Have you ever considered if we could be more than friends?” or “Crazy thought: I wonder what we’d be like as a married couple.” If they’re interested, they’ll follow you down this conversational path and tell you what you need to know. Or they may not see you that way. Regardless, it’s worth bringing up. If they’re not interested, what’s the worst that could happen? Make a joke and move on.