Help Needed - Horror Film Name

[THF90]

There is this movie that I saw on Amazon Prime a couple years back and I can’t remember what it is called.

It’s from the late 70’s or early 80’s.

It has a guy who might have been insane, but throughout the film he is heading towards somewhere.

What I mostly remember is the end.

The guy finds a house and goes inside and there’s people talking on the phone, but they leave and I think kids are left.

The guy goes into a hallway or a room trying to get to one of the kids, which I believe was his kid, but that was unknown to the watcher until later in the film, but he gets blown away on the stairs in the house.

Anyone know what this was called?