"The family contacted churches and clairvoyants "
I mean really, so sad she contacted a clairvoyant when a clairvoyant operates under demonic powers... realllllyyy?

" make an altar in the basement and burn sage and sulfur throughout the house"

Worse advice ever, a demon possessed person telling them how to get rid of a demons in a demon infested house.... Instead they did the opposite and probably invited much more.

What's next, sprinkle some sea salt around the house? LOL the demons will just literally laugh their butts off. Get out of here.

And don't get me started bringing a catholic priest in there, they got screwed on so many levels.

Here is the answer and this is from experience because I grew up in a demon infested house. Here it goes

Answer: Jesus.