Because he's cuckoo for cocoa puffs. It's either "happening" or it isn't, there's no middle ground. Personally, I am not a believer of such activities, but if there was irrefutable evidence, over and over again, I'd probably get the **** out of there. Moving to a different location should "In Theory" isolate the craziness to the house or to you.
Let me try and get my crazy brain around something here...

1. My
oldest daughter (kid) has been petrified to be in certain areas of our home alone since we moved in six years ago...claiming "ghosts" in a part of the basement and dining room...only to quickly ask my wife and I "there's no such thing as ghosts, for real, right?!" The same spots in the house where I have seen/felt some of the strongest presences (and no gas leaks, no CO, etc, for all the haters/skeptics out there).
2. My sister (in her 30s) and my two nieces
woke up screaming one night after seeing two children in the third floor bedroom with them, then shortly after, a window opened on its own with such force that a pane of glass shattered. We had said nothing about any "extra roommates" to them before their stay, as we didn't want to make them nervous or freak them out.
3. My youngest niece was
awoken in our living room in the middle of the night by a girl in a dress with a ribbon in her hair...asking if she had "seen her Mama," only to have the girl vanish into thin air.
4. A person with no ties to the home who
claims certain "gifts" came in and, uninformed/unprovoked, described some of the IDENTICAL things (right down to names or exact locations in the home where activity is occurring) that I and others have been seeing/feeling/hearing over the past several years. She also gave names of people which I also had been given without any prior knowledge of the situation (no, not "John" or "Mary" either, lol).
So...multiple people experiencing multiple, similar-yet-separate experiences in similar areas of the home. Also, no CO/radon/gas problems of any kind (believe me, we've checked). So, is your assessment then that my daughter, my sister, my two nieces, the "medium" friend of mine and I are all completely off our rockers?! Or if we're not crazy, what can be defined as irrefutable evidence? Multiple people experiencing similar things at different times (without being lead to expect it)...or something one can post on YouTube for people 1,000 miles away to cast their vote without any real knowledge of the situation, or experience in the actual space?