My father has a wood burning boiler connected to the same water circuit that heats the radiators as his air-water heat pump. Originally when the house was built

My father has a wood burning boiler connected to the same water circuit that heats the radiators as his air-water heat pump. Originally when the house was built it was a wood-oil combi boiler, later on the oil burner was ripped out and the heat pump installed (at that point there were government grants available for replacing oil heating with heat pumps). It does work well, and when it gets cold in the winter and the efficiency of the heat pump drops, he burns wood. But honestly the system is a jungle of pipes and valves, and the guys who did the heat pump installation were unable to wrap their heads around it. Luckily my father is a handy guy so he was able to do it himself. But I'm thinking if one were to do something like this from scratch, without the history of the existing boiler already being there and installed, I wouldn't bother with it. Just have a few good old school wood stoves with significant thermal mass (masonry heater or whatever you call them in the US) in the house that you can use to provide extra heat when it's cold, and as backup in case there's an electricity outage.