How to approach a non listing

[Mun Sihota]

I was wondering if I could get some advice from the community on how to approach this situation. I'm currently renting a half duplex, adjacent to us is a daycare, and directly behind the daycare is a retired gentlemen living in a 3Br/2ba home from the mid 50's. My wife, two toddlers and I are wanting to buy sometime towards the end of this year, we love the area and would like to purchase his home as we love the neighborhood. I was hoping to get some advice on how I could approach him as currently his home isn't listed and we aren't in an immediate rush to buy, would the right approach be to build some rapport first? Have my son throw a frisbee on his yard and knock on his door to ask if we could retrieve it to start conversation? A different approach He's got a good size yard our kids would love as we are outgrowing our half duplex with a tiny yard, but just not sure how to get the ball rolling here. Any help would be greatly appreciated, thanks a lot.