While baseboard or radiant may lend itself to wood boiler use more easily I do not see why exchanger use is not a viable option after all isn’t that a proven option in air conditioning use as well as large scale open area heating ? The heating of DHW is also an advantage not offered with the outdoor forced air units. Don’t get me wrong all these units have good applications and for a smaller home it might be a great solution.
No doubt he is in the boiler room, and we make boilers work. However, boilers are more expensive appliances than stoves. The stove I described costs 600 dollars and can heat 2000 feet of space. A similar boiler may cost 3600. So you have to do a lot of DHW heating to justify it.
Also, the fact that he doesn't have the infrastructure to heat radiantly with hot water has to do with overall comfort. I prefer radiant heat to force air. I know others feel the same way. Many people don't even know since they haven't been exposed to radiant before.
He may want to add the infrastructure, but it isn't cheap.
I try to balance economy with comfort. Your looking at a large investment in time and money- if you choose a boiler over forced air.
If you don't value the difference of radiant heat over forced then you can do well with stove. You loose options like heat storage and gasification efficiencies and some other things as well, but for 1G and 1 days work your off the gas grid.