Never heard of that specific one but old farmhouses in isolated spots do seem to attract a lot of stories. Could just be local legend that's grown legs over the years, or there's something genuinely worth looking into.
What's your cousin actually experienced there? That'd help separate the "spooky vibes because its old and creaky" type stuff from anything that sounds like genuine poltergeist activity or residual haunting. Because those are very different things and people tend to lump it all together.
I've investigated a few old rural properties in Cornwall and half the time the "haunting" turns out to be subsidence, animals in the walls, that sort of thing. The other half... well, you get cases that are harder to explain away neatly.
Anyone local to Delphos on here who knows the history of the place? Always helps to have some background before jumping to conclusions.